Failed to deploy web package to App Service. Service Unavailable (CODE: 503)

Question

I am trying to deploy my app to an Azure app service via Azure Dev Ops pipelines. The app builds okay, but during the deploy phase, I get the following error.

2023-01-12T19:23:13.1683884Z ##[error]Failed to deploy web package to App Service.
2023-01-12T19:23:13.1696403Z ##[error]Error: Error: Failed to deploy web package to App Service. Service Unavailable (CODE: 503)

It has failed consistently multiple times in a row, after working fine for the past couple of weeks.

Full log

2023-01-12T19:21:10.6967333Z ##[section]Starting: Deploy
2023-01-12T19:21:10.6981944Z ==============================================================================
2023-01-12T19:21:10.6982213Z Task         : Azure App Service deploy
2023-01-12T19:21:10.6982366Z Description  : Deploy to Azure App Service a web, mobile, or API app using Docker, Java, .NET, .NET Core, Node.js, PHP, Python, or Ruby
2023-01-12T19:21:10.6982681Z Version      : 4.214.0
2023-01-12T19:21:10.6982809Z Author       : Microsoft Corporation
2023-01-12T19:21:10.6982961Z Help         : https://aka.ms/azureappservicetroubleshooting
2023-01-12T19:21:10.6983137Z ==============================================================================
2023-01-12T19:21:11.2444263Z Got service connection details for Azure App Service:'REDACTED'
2023-01-12T19:22:18.8337786Z Package deployment using ZIP Deploy initiated.
2023-01-12T19:23:13.1683884Z ##[error]Failed to deploy web package to App Service.
2023-01-12T19:23:13.1696403Z ##[error]Error: Error: Failed to deploy web package to App Service. Service Unavailable (CODE: 503)
2023-01-12T19:23:13.9090032Z Successfully added release annotation to the Application Insight : [REDACTED]
2023-01-12T19:23:14.0064590Z ##[warning]Error: Failed to update deployment history. Error: Service Unavailable (CODE: 503)
2023-01-12T19:23:14.2708516Z App Service Application URL: https://REDACTED.azurewebsites.net
2023-01-12T19:23:14.2790032Z ##[section]Finishing: Deploy

I tried to redeploy an older release that previously worked, but I got the same errors.

I also tried to publish to my app service from Visual Studio. It failed with the following error.

Error MSB4018: The "ZipDeploy" task failed unexpectedly.

Full Error

Error MSB4018: The "ZipDeploy" task failed unexpectedly.
System.AggregateException: One or more errors occurred. ---> System.Net.Http.HttpRequestException: Error while copying content to a stream. ---> System.IO.IOException: Unable to read data from the transport connection: An established connection was aborted by the software in your host machine. ---> System.Net.Sockets.SocketException: An established connection was aborted by the software in your host machine
   at System.Net.Sockets.Socket.BeginReceive(Byte[] buffer, Int32 offset, Int32 size, SocketFlags socketFlags, AsyncCallback callback, Object state)
   at System.Net.Sockets.NetworkStream.BeginRead(Byte[] buffer, Int32 offset, Int32 size, AsyncCallback callback, Object state)
   --- End of inner exception stack trace ---
   at System.Net.ConnectStream.EndRead(IAsyncResult asyncResult)
   at System.Net.Http.HttpClientHandler.WebExceptionWrapperStream.EndRead(IAsyncResult asyncResult)
   at System.Net.Http.StreamToStreamCopy.StartRead()
   --- End of inner exception stack trace ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.NET.Sdk.Publish.Tasks.ZipDeploy.HttpClientHelpers.<PostWithBasicAuthAsync>d__0.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.NET.Sdk.Publish.Tasks.ZipDeploy.ZipDeploy.<ZipDeployAsync>d__26.MoveNext()
   --- End of inner exception stack trace ---
   at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions)
   at System.Threading.Tasks.Task.Wait(Int32 millisecondsTimeout, CancellationToken cancellationToken)
   at Microsoft.NET.Sdk.Publish.Tasks.ZipDeploy.ZipDeploy.Execute()
   at Microsoft.Build.BackEnd.TaskExecutionHost.Microsoft.Build.BackEnd.ITaskExecutionHost.Execute()
   at Microsoft.Build.BackEnd.TaskBuilder.<ExecuteInstantiatedTask>d__26.MoveNext()
---> (Inner Exception #0) System.Net.Http.HttpRequestException: Error while copying content to a stream. ---> System.IO.IOException: Unable to read data from the transport connection: An established connection was aborted by the software in your host machine. ---> System.Net.Sockets.SocketException: An established connection was aborted by the software in your host machine
   at System.Net.Sockets.Socket.BeginReceive(Byte[] buffer, Int32 offset, Int32 size, SocketFlags socketFlags, AsyncCallback callback, Object state)
   at System.Net.Sockets.NetworkStream.BeginRead(Byte[] buffer, Int32 offset, Int32 size, AsyncCallback callback, Object state)
   --- End of inner exception stack trace ---
   at System.Net.ConnectStream.EndRead(IAsyncResult asyncResult)
   at System.Net.Http.HttpClientHandler.WebExceptionWrapperStream.EndRead(IAsyncResult asyncResult)
   at System.Net.Http.StreamToStreamCopy.StartRead()
   --- End of inner exception stack trace ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.NET.Sdk.Publish.Tasks.ZipDeploy.HttpClientHelpers.<PostWithBasicAuthAsync>d__0.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.NET.Sdk.Publish.Tasks.ZipDeploy.ZipDeploy.<ZipDeployAsync>d__26.MoveNext()<---

Could this a temporary problem with the zip deployment service? The Azure service status page doesn't currently show any issues.

Answer 1

Turns out my App Service was overloaded. I scaled-up to the next plan, and I was able to deploy again.