diff --git a/un.awk b/un.awk
index 1c04a87..074ea67 100644
--- a/un.awk
+++ b/un.awk
@@ -169,6 +169,17 @@ function execute(filename    , api_key) {
     # Clean up
     system("rm -f " tmp)
 
+    # Check for timestamp authentication errors
+    if (match(response, /timestamp/) && (match(response, /401/) || match(response, /expired/) || match(response, /invalid/))) {
+        print RED "Error: Request timestamp expired (must be within 5 minutes of server time)" RESET > "/dev/stderr"
+        print YELLOW "Your computer's clock may have drifted." RESET > "/dev/stderr"
+        print "Check your system time and sync with NTP if needed:" > "/dev/stderr"
+        print "  Linux:   sudo ntpdate -s time.nist.gov" > "/dev/stderr"
+        print "  macOS:   sudo sntp -sS time.apple.com" > "/dev/stderr"
+        print "  Windows: w32tm /resync" > "/dev/stderr"
+        exit 1
+    }
+
     # Parse stdout from response (simple regex)
     if (match(response, /"stdout":"([^"]*)"/, arr)) {
         stdout = arr[1]
diff --git a/un.cpp b/un.cpp
index a514e51..3394ccc 100644
--- a/un.cpp
+++ b/un.cpp
@@ -109,6 +109,19 @@ string exec_curl(const string& cmd) {
         result += buffer;
     }
     pclose(pipe);
+
+    // Check for timestamp authentication errors
+    if (result.find("timestamp") != string::npos &&
+        (result.find("401") != string::npos || result.find("expired") != string::npos || result.find("invalid") != string::npos)) {
+        cerr << RED << "Error: Request timestamp expired (must be within 5 minutes of server time)" << RESET << endl;
+        cerr << YELLOW << "Your computer's clock may have drifted." << RESET << endl;
+        cerr << "Check your system time and sync with NTP if needed:" << endl;
+        cerr << "  Linux:   sudo ntpdate -s time.nist.gov" << endl;
+        cerr << "  macOS:   sudo sntp -sS time.apple.com" << endl;
+        cerr << "  Windows: w32tm /resync" << endl;
+        exit(1);
+    }
+
     return result;
 }
 
diff --git a/un.cr b/un.cr
index 7f3c3c4..6cb19b0 100644
--- a/un.cr
+++ b/un.cr
@@ -130,7 +130,17 @@ def api_request(endpoint : String, public_key : String, secret_key : String?, me
 
     JSON.parse(response.body)
   rescue ex
-    STDERR.puts "#{RED}Error: Request failed: #{ex.message}#{RESET}"
+    error_msg = ex.message || ""
+    if error_msg.downcase.includes?("timestamp") || (response && response.status_code == 401 && response.body.downcase.includes?("timestamp"))
+      STDERR.puts "#{RED}Error: Request timestamp expired (must be within 5 minutes of server time)#{RESET}"
+      STDERR.puts "#{YELLOW}Your computer's clock may have drifted.#{RESET}"
+      STDERR.puts "Check your system time and sync with NTP if needed:"
+      STDERR.puts "  Linux:   sudo ntpdate -s time.nist.gov"
+      STDERR.puts "  macOS:   sudo sntp -sS time.apple.com"
+      STDERR.puts "  Windows: w32tm /resync"
+    else
+      STDERR.puts "#{RED}Error: Request failed: #{ex.message}#{RESET}"
+    end
     exit 1
   end
 end
diff --git a/un.d b/un.d
index f918112..9b67077 100644
--- a/un.d
+++ b/un.d
@@ -121,7 +121,22 @@ string buildAuthHeaders(string method, string path, string body, string publicKe
 
 string execCurl(string cmd) {
     auto result = executeShell(cmd);
-    return result.output;
+    string output = result.output;
+
+    // Check for timestamp authentication errors
+    import std.algorithm : canFind;
+    if (output.canFind("timestamp") &&
+        (output.canFind("401") || output.canFind("expired") || output.canFind("invalid"))) {
+        stderr.writefln("%sError: Request timestamp expired (must be within 5 minutes of server time)%s", RED, RESET);
+        stderr.writefln("%sYour computer's clock may have drifted.%s", YELLOW, RESET);
+        stderr.writeln("Check your system time and sync with NTP if needed:");
+        stderr.writeln("  Linux:   sudo ntpdate -s time.nist.gov");
+        stderr.writeln("  macOS:   sudo sntp -sS time.apple.com");
+        stderr.writeln("  Windows: w32tm /resync");
+        exit(1);
+    }
+
+    return output;
 }
 
 void cmdExecute(string sourceFile, string[] envs, bool artifacts, string network, int vcpu, string publicKey, string secretKey) {
diff --git a/un.dart b/un.dart
index 5f556d1..2b03262 100644
--- a/un.dart
+++ b/un.dart
@@ -172,6 +172,19 @@ Future<Map<String, dynamic>> apiRequestCurl(String endpoint, String method, Stri
     }
 
     final response = result.stdout as String;
+
+    // Check for timestamp authentication errors
+    if (response.toLowerCase().contains('timestamp') &&
+        (response.contains('401') || response.toLowerCase().contains('expired') || response.toLowerCase().contains('invalid'))) {
+      stderr.writeln('${red}Error: Request timestamp expired (must be within 5 minutes of server time)$reset');
+      stderr.writeln('${yellow}Your computer\'s clock may have drifted.$reset');
+      stderr.writeln('Check your system time and sync with NTP if needed:');
+      stderr.writeln('  Linux:   sudo ntpdate -s time.nist.gov');
+      stderr.writeln('  macOS:   sudo sntp -sS time.apple.com');
+      stderr.writeln('  Windows: w32tm /resync');
+      exit(1);
+    }
+
     return jsonDecode(response) as Map<String, dynamic>;
   } finally {
     await tempFile.delete();
diff --git a/un.groovy b/un.groovy
index 3d1e889..f4dc222 100644
--- a/un.groovy
+++ b/un.groovy
@@ -168,6 +168,18 @@ def apiRequest(endpoint, method, data, publicKey, secretKey) {
             System.exit(1)
         }
 
+        // Check for timestamp authentication errors
+        if (output.toLowerCase().contains('timestamp') &&
+            (output.contains('401') || output.toLowerCase().contains('expired') || output.toLowerCase().contains('invalid'))) {
+            System.err.println("${RED}Error: Request timestamp expired (must be within 5 minutes of server time)${RESET}")
+            System.err.println("${YELLOW}Your computer's clock may have drifted.${RESET}")
+            System.err.println("Check your system time and sync with NTP if needed:")
+            System.err.println("  Linux:   sudo ntpdate -s time.nist.gov")
+            System.err.println("  macOS:   sudo sntp -sS time.apple.com")
+            System.err.println("  Windows: w32tm /resync")
+            System.exit(1)
+        }
+
         return output
     } finally {
         tempFile.delete()
diff --git a/un.jl b/un.jl
index 35bcbf9..fefb215 100755
--- a/un.jl
+++ b/un.jl
@@ -141,7 +141,17 @@ function api_request(endpoint::String, public_key::String, secret_key::String; m
         return JSON.parse(String(response.body))
     catch e
         if isa(e, HTTP.ExceptionRequest.StatusError)
-            println(stderr, "$(RED)Error: HTTP $(e.status) - $(String(e.response.body))$(RESET)")
+            error_body = String(e.response.body)
+            if e.status == 401 && occursin("timestamp", lowercase(error_body))
+                println(stderr, "$(RED)Error: Request timestamp expired (must be within 5 minutes of server time)$(RESET)")
+                println(stderr, "$(YELLOW)Your computer's clock may have drifted.$(RESET)")
+                println(stderr, "Check your system time and sync with NTP if needed:")
+                println(stderr, "  Linux:   sudo ntpdate -s time.nist.gov")
+                println(stderr, "  macOS:   sudo sntp -sS time.apple.com")
+                println(stderr, "  Windows: w32tm /resync")
+            else
+                println(stderr, "$(RED)Error: HTTP $(e.status) - $(error_body)$(RESET)")
+            end
         else
             println(stderr, "$(RED)Error: Request failed: $e$(RESET)")
         end
diff --git a/un.kt b/un.kt
index 60ebd72..dd05a3d 100644
--- a/un.kt
+++ b/un.kt
@@ -530,6 +530,15 @@ fun apiRequest(endpoint: String, method: String, data: Map<String, Any>?, public
 
     if (connection.responseCode !in 200..299) {
         val error = connection.errorStream?.bufferedReader()?.readText() ?: ""
+        if (connection.responseCode == 401 && error.lowercase().contains("timestamp")) {
+            System.err.println("${RED}Error: Request timestamp expired (must be within 5 minutes of server time)${RESET}")
+            System.err.println("${YELLOW}Your computer's clock may have drifted.${RESET}")
+            System.err.println("Check your system time and sync with NTP if needed:")
+            System.err.println("  Linux:   sudo ntpdate -s time.nist.gov")
+            System.err.println("  macOS:   sudo sntp -sS time.apple.com")
+            System.err.println("  Windows: w32tm /resync")
+            exitProcess(1)
+        }
         throw RuntimeException("HTTP ${connection.responseCode} - $error")
     }
 
diff --git a/un.nim b/un.nim
index 97fe60b..b550fa2 100644
--- a/un.nim
+++ b/un.nim
@@ -98,6 +98,17 @@ proc buildAuthHeaders(meth: string, path: string, body: string, publicKey: strin
 proc execCurl(cmd: string): string =
   result = execProcess(cmd)
 
+  # Check for timestamp authentication errors
+  if result.contains("timestamp") and
+     (result.contains("401") or result.contains("expired") or result.contains("invalid")):
+    stderr.writeLine(RED & "Error: Request timestamp expired (must be within 5 minutes of server time)" & RESET)
+    stderr.writeLine(YELLOW & "Your computer's clock may have drifted." & RESET)
+    stderr.writeLine("Check your system time and sync with NTP if needed:")
+    stderr.writeLine("  Linux:   sudo ntpdate -s time.nist.gov")
+    stderr.writeLine("  macOS:   sudo sntp -sS time.apple.com")
+    stderr.writeLine("  Windows: w32tm /resync")
+    quit(1)
+
 proc cmdExecute(sourceFile: string, envs: seq[string], artifacts: bool, network: string, vcpu: int, publicKey: string, secretKey: string) =
   let lang = detectLanguage(sourceFile)
   if lang == "":
diff --git a/un.ps1 b/un.ps1
index b332709..5497e71 100644
--- a/un.ps1
+++ b/un.ps1
@@ -111,7 +111,17 @@ function Invoke-Api {
         }
         return $response
     } catch {
-        Write-Error "Error: $($_.Exception.Message)"
+        $errorMsg = $_.Exception.Message
+        if ($errorMsg -match "401" -and $errorMsg -match "timestamp") {
+            Write-Host "`e[31mError: Request timestamp expired (must be within 5 minutes of server time)`e[0m" -ForegroundColor Red
+            Write-Host "`e[33mYour computer's clock may have drifted.`e[0m" -ForegroundColor Yellow
+            Write-Host "Check your system time and sync with NTP if needed:"
+            Write-Host "  Linux:   sudo ntpdate -s time.nist.gov"
+            Write-Host "  macOS:   sudo sntp -sS time.apple.com"
+            Write-Host "  Windows: w32tm /resync"
+        } else {
+            Write-Error "Error: $errorMsg"
+        }
         exit 1
     }
 }
diff --git a/un.rs b/un.rs
index 69cdae3..22f6eb1 100644
--- a/un.rs
+++ b/un.rs
@@ -228,7 +228,20 @@ fn api_request(endpoint: &str, method: &str, body: Option<&str>, public_key: &st
         process::exit(1);
     }
 
-    String::from_utf8_lossy(&output.stdout).to_string()
+    let result = String::from_utf8_lossy(&output.stdout).to_string();
+
+    // Check for timestamp authentication errors
+    if result.contains("timestamp") && (result.contains("401") || result.contains("expired") || result.contains("invalid")) {
+        eprintln!("{}Error: Request timestamp expired (must be within 5 minutes of server time){}", RED, RESET);
+        eprintln!("{}Your computer's clock may have drifted.{}", YELLOW, RESET);
+        eprintln!("Check your system time and sync with NTP if needed:");
+        eprintln!("  Linux:   sudo ntpdate -s time.nist.gov");
+        eprintln!("  macOS:   sudo sntp -sS time.apple.com");
+        eprintln!("  Windows: w32tm /resync");
+        process::exit(1);
+    }
+
+    result
 }
 
 fn cmd_execute(
diff --git a/un.tcl b/un.tcl
index df10833..3176936 100755
--- a/un.tcl
+++ b/un.tcl
@@ -151,8 +151,17 @@ proc api_request {endpoint method data public_key secret_key} {
     ::http::cleanup $token
 
     if {$status ne "ok" || ($ncode != 200 && $ncode != 201)} {
-        puts stderr "${::RED}Error: HTTP $ncode${::RESET}"
-        puts stderr $body
+        if {$ncode == 401 && [string match -nocase "*timestamp*" $body]} {
+            puts stderr "${::RED}Error: Request timestamp expired (must be within 5 minutes of server time)${::RESET}"
+            puts stderr "${::YELLOW}Your computer's clock may have drifted.${::RESET}"
+            puts stderr "Check your system time and sync with NTP if needed:"
+            puts stderr "  Linux:   sudo ntpdate -s time.nist.gov"
+            puts stderr "  macOS:   sudo sntp -sS time.apple.com"
+            puts stderr "  Windows: w32tm /resync"
+        } else {
+            puts stderr "${::RED}Error: HTTP $ncode${::RESET}"
+            puts stderr $body
+        }
         exit 1
     }
 
diff --git a/un.ts b/un.ts
index 7ec69da..e731e69 100644
--- a/un.ts
+++ b/un.ts
@@ -191,7 +191,16 @@ function apiRequest(endpoint: string, method: string = "GET", data: any = null,
             resolve(body);
           }
         } else {
-          console.error(`${RED}Error: HTTP ${res.statusCode} - ${body}${RESET}`);
+          if (res.statusCode === 401 && body.toLowerCase().includes('timestamp')) {
+            console.error(`${RED}Error: Request timestamp expired (must be within 5 minutes of server time)${RESET}`);
+            console.error(`${YELLOW}Your computer's clock may have drifted.${RESET}`);
+            console.error("Check your system time and sync with NTP if needed:");
+            console.error("  Linux:   sudo ntpdate -s time.nist.gov");
+            console.error("  macOS:   sudo sntp -sS time.apple.com");
+            console.error("  Windows: w32tm /resync");
+          } else {
+            console.error(`${RED}Error: HTTP ${res.statusCode} - ${body}${RESET}`);
+          }
           process.exit(1);
         }
       });
diff --git a/un.v b/un.v
index 7185bb0..a07b765 100644
--- a/un.v
+++ b/un.v
@@ -97,7 +97,21 @@ fn escape_json(s string) string {
 
 fn exec_curl(cmd string) string {
 	result := os.execute(cmd)
-	return result.output
+	output := result.output
+
+	// Check for timestamp authentication errors
+	if output.contains('timestamp') &&
+		(output.contains('401') || output.contains('expired') || output.contains('invalid')) {
+		eprintln('${red}Error: Request timestamp expired (must be within 5 minutes of server time)${reset}')
+		eprintln('${yellow}Your computer\'s clock may have drifted.${reset}')
+		eprintln('Check your system time and sync with NTP if needed:')
+		eprintln('  Linux:   sudo ntpdate -s time.nist.gov')
+		eprintln('  macOS:   sudo sntp -sS time.apple.com')
+		eprintln('  Windows: w32tm /resync')
+		exit(1)
+	}
+
+	return output
 }
 
 fn extract_json_string(json string, key string) string {