Our deployment ran smooth for weeks. But suddenly and without warning and only for one app, the “Bad Gateway” error appeared when deploying Azure DevOps to Azure App Service.
12021-10-02T18:22:51.9578529Z ##[section]Starting: Deploy to !!! PROD STAGE !!!
22021-10-02T18:22:51.9717826Z ==============================================================================
32021-10-02T18:22:51.9718244Z Task : Azure App Service deploy
42021-10-02T18:22:51.9718657Z Description : Deploy to Azure App Service a web, mobile or API app using Docker, Java, .NET, .NET Core, Node.js, PHP, Python or Ruby
52021-10-02T18:22:51.9719036Z Version : 4.184.4
62021-10-02T18:22:51.9719264Z Author : Microsoft Corporation
72021-10-02T18:22:51.9719571Z Help : https://aka.ms/azureappservicetroubleshooting
82021-10-02T18:22:51.9720056Z ==============================================================================
92021-10-02T18:22:52.5969763Z Got service connection details for Azure App Service:'mypage'
102021-10-02T18:23:54.6310344Z Package deployment using ZIP Deploy initiated.
112021-10-02T18:24:52.6365880Z ##[error]Failed to deploy web package to App Service.
122021-10-02T18:24:52.6380801Z ##[error]Error: Error: Failed to deploy web package to App Service. Bad Gateway (CODE: 502)
132021-10-02T18:24:53.9605307Z Successfully added release annotation to the Application Insight :mypage
142021-10-02T18:24:54.1466996Z ##[warning]Error: Failed to update deployment history. Error: Bad Gateway (CODE: 502)
152021-10-02T18:24:54.4910095Z App Service Application URL: https://myurl.azurewebsites.net
162021-10-02T18:24:54.5026817Z ##[section]Finishing: Deploy to !!! PROD STAGE !!!
Spent a lot of time with Google on what this error could be. Many wrote to reset the App Service Plan, move the app to another region, but in the end it was very simple:
Just manually select a different app scale size (for example, from S1 to P1V3) and then switch back again. Suddenly everything worked again… ¯_(ツ)_/¯
Related articles
Mar 10, 2026 · 15 min read
.NET NuGet Trusted Publishing with GitHub Actions
Publishing NuGet packages has traditionally required one uncomfortable compromise: a long-lived API key had to exist somewhere in the …
Mar 09, 2026 · 7 min read
C# 15 Unions: Unions are finally in .NET
After many years of workarounds, design discussions and library-level substitutes, unions are finally becoming a first-class part of C#. The …
Mar 02, 2026 · 19 min read
Unio: High-Performance Discriminated Unions for C#
C# is a powerful language, but there is one road it has not yet fully paved: native discriminated union types. Developers have been working …
Author
BEN ABT
Ben is a Principal Software Engineer at Medialesson.de, with a strong focus on .NET and Microsoft Azure. In his professional role, he designs and builds highly scalable platforms for hybrid and cloud-based scenarios. He also advises companies and C-levels on migrating to the sovereign cloud.
He runs myCSharp.de, the largest and most active German-speaking C# community forum, actively contributes to both his own and external open-source projects and regularly shares his knowledge through his blog, at community events, conferences and as a writer for technical magazines.
Let's Work Together
Looking for an experienced Platform Architect or Engineer for your next project? Whether it's cloud migration, platform modernization or building new solutions from scratch - I'm here to help you succeed.
Comments