HTTP Error 500.0 - ANCM In-Process Handler Load Failure when publishing a Blazor server-side application

Question

To start, I'd just like to say that I am still very new to creating websites, and have next to no experience with the publishing/hosting process. Forgive me if this is an easy fix, but after some unsuccessful researching, I am pretty stuck.

I've created a personal website using Blazor server-side .NET core 3.1 that I would like to publish. I've purchased the domain name and purchased a hosting plan for a windows server, that to my understanding, supports .NET core 3.1 applications.

The website works perfectly when I launch it via IIS Express in Visual Studio 2019 Community. However, when I upload my site through FTP, though the publish says it's successful without error on Visual Studio and it appears that all my files are present and accounted for on the FTP file manager, when I navigate to my site, it gives me the following error: HTTP Error 500.0 - ANCM In-Process Handler Load Failure.

How do I go about handling this?

Answer 1

There is really two things to check.

The first one is that your application may be failing to start because of a missing file, maybe it's unable to connect to a startup service (Keyvault for instance etc).

First from your publish folder, can you run

dotnet yourapplication.dll

And check if it runs. If you see an error message, then you will have to resolve this error until it starts fine. Even if it does start fine, you should make sure that your configuration is correct on the remote server. e.g. Are you sure it's connecting to the right database? Is the way it's trying to read config correct?

The second issue you should take a look at is make 100% sure that your host supports .NET Core 3.1 (Or name them here so others can check for you).