This problem will occur if ASP.NET is not installed correctly in your server. Please follow the steps below to rectify this issue:

  1. Navigate to C:\Windows\Microsoft.NET\Framework64\v4.0.30319
  2. Type the command aspnet_regiis -iru 
    -iru - Install this version of ASP.NET. If there are any existing applications that uses ASP.NET, it will not change IIS configuration to use this version.
  3. aspnet_regiis -iru
  4. Make sure BizTalk360 application pool is configured to run .NET Framework 4.0 and Integrated mode
  5. Reset IIS