diff --git a/staging/cse/windows/kubernetesfunc.ps1 b/staging/cse/windows/kubernetesfunc.ps1
index 0cc784796ea..ec2ff53c04b 100644
--- a/staging/cse/windows/kubernetesfunc.ps1
+++ b/staging/cse/windows/kubernetesfunc.ps1
@@ -182,6 +182,7 @@ function Check-APIServerConnectivity {
     )
     Logs-To-Event -TaskName "AKS.WindowsCSE.CheckAPIServerConnectivity" -TaskMessage "Start to check API server connectivity."
     $retryCount=0
+    $LastException=$null
 
     do {
         $retryString="${retryCount}/${MaxRetryCount}"
@@ -201,17 +202,30 @@ function Check-APIServerConnectivity {
             }
             $tcpClient.Close()
         } catch [System.AggregateException] {
-            Write-Log "Retry ${retryString}: Failed to connect to API server $MasterIP. AggregateException: " + $_.Exception.ToString()
+            Logs-To-Event -TaskName "AKS.WindowsCSE.CheckAPIServerConnectivity" -TaskMessage "Retry ${retryString}: Failed to connect to API server $MasterIP. AggregateException: " + $_.Exception.ToString()
+            $LastException = $_.Exception.ToString()
         } catch {
-            Write-Log "Retry ${retryString}: Failed to connect to API server $MasterIP. Error: $_"
-        }
+            Logs-To-Event -TaskName "AKS.WindowsCSE.CheckAPIServerConnectivity" -TaskMessage "Retry ${retryString}: Failed to connect to API server $MasterIP. Error: $_"
+            $LastException = "$_"
+      }
 
         $retryCount++
         Write-Log "Retry ${retryString}: Sleep $RetryInterval and then retry to connect to API server"
         Sleep $RetryInterval
     } while ($retryCount -lt $MaxRetryCount)
 
-    Set-ExitCode -ExitCode $global:WINDOWS_CSE_ERROR_CHECK_API_SERVER_CONNECTIVITY -ErrorMessage "Failed to connect to API server $MasterIP after $retryCount retries"
+    $lastExceptionMessage = ""
+    if ($LastException -ne $null) {
+        if ($LastException.Exception -ne $null -and -not [string]::IsNullOrEmpty($LastException.Exception.Message)) {
+            $lastExceptionMessage = $LastException.Exception.Message
+        } else {
+            $lastExceptionMessage = $LastException.ToString()
+        }
+        # Normalize any CR/LF in the exception message to spaces to keep ErrorMessage single-line.
+        $lastExceptionMessage = $lastExceptionMessage -replace "(`r|`n)+", " "
+    }
+
+    Set-ExitCode -ExitCode $global:WINDOWS_CSE_ERROR_CHECK_API_SERVER_CONNECTIVITY -ErrorMessage "Failed to connect to API server $MasterIP after $retryCount retries. Last exception: $lastExceptionMessage"
 }
 
 function Get-CACertificates {