Troubleshooting

Turn on ASP.NET Core debug logging Enable the stdout log to see why your application fails to start. Read website logs Use the access log, event log and HTTP platform log to find the cause of a problem. Node.js debug logging (HttpPlatform) Capture the output of a Node.js, Angular SSR or Next.js application.

HTTP Error 500 - the application failed to start How to find out why your application returns error 500 or 500.30, and the most common causes. HTTP Error 403 - forbidden Your files are probably not in the wwwroot folder - here is how to check. HTTP Error 400 - invalid hostname The AllowedHosts setting of your application does not match your domain. 404 on the home page of a Web API Why a Web API returns 404 on its root address, how to show Swagger and how to serve a front end. CORS errors when calling your API Allow your front end to call an API hosted on another domain. Files are locked during deployment Fix the 'file is in use' error when publishing a new version. Cannot connect to the database A checklist for login failures, timeouts and certificate errors. Database connection blocked after failed logins Your IP address is blocked for 24 hours after too many wrong passwords. Database disappeared or was deleted What happens when a DROP DATABASE command is run by mistake. Free website or database was archived Free services that are not used for 6 months are archived automatically. Website disabled by the security system Why a website is suspended when it starts Chrome, FFmpeg or another executable. Application keeps restarting or loses sessions The usual reasons an application is restarted and how to find the cause. Website works for you but not for some visitors How to tell a problem on the server from a problem with DNS or an internet provider.