Error when running any program

The framework 'Microsoft.NETCore.App', version '3.1.0' was not found.
- The following frameworks were found:
5.0.4 at [/snap/dotnet-sdk/116/shared/Microsoft.NETCore.App]

You can resolve the problem by installing the specified framework and/or SDK.

The specified framework can be found at:
- https://aka.ms/dotnet-core-applaunch?framework=Microsoft.NETCore.App&framework_version=3.1.0&arch=x64&rid=ubuntu.20.10-x64

Process finished with exit code 150.

when i do dotnet --version

5.0.201

what is the issue