Azure App service - .Net Core - Failed to start application /LM/W3SVC/###/ROOT, ErrorCode "0x800700c1"

After deploying to a newly created Azure App Service, I get this error:

HTTP Error 500.0 - ANCM In-Process Handler Load Failure

eventlog.xml shows these two lines:

<Data>Failed to start application '/LM/W3SVC/1773510456/ROOT', ErrorCode '0x800700c1'.</Data>

And

<Data>Could not find inprocess request handler. Captured output from invoking hostfxr: </Data>

I am deploying a 64 bit Web Api (<RuntimeIdentifier>win-x64</RuntimeIdentifier> inside the csproj).

Googling the errors reveals that it's related to a 64bit/32bit mismatch. Azure App Service is set to 32 bit, this needs to be changed. Copied and modified from AspNetCore.Docs Issue 13013 :

Azure App Service does have both the 32- and 64-bit runtimes available since .NET Core 2.2 was released. To set the Platform to 64 Bit, go to the App Service > Configuration > General settings > Platform settings > Platform > 64 bit. Note that you need to have a Basic or higher service app plan.