Under Linux, I cannot run my project; libhostpolicy.so is missing

I installed Rider on Linux, but when I want to run my project, I get this error:

"""

/usr/share/dotnet/dotnet /home/jabba/Dropbox/csharp/Reloaded/HelloWorld/bin/Debug/netcoreapp3.1/HelloWorld.dll
A fatal error was encountered. The library 'libhostpolicy.so' required to execute the application was not found in '/mnt/UBUNTU_OPT/Dropbox/csharp/Reloaded/HelloWorld/bin/Debug/netcoreapp3.1/'.
Failed to run as a self-contained app. If this should be a framework-dependent app, add the /mnt/UBUNTU_OPT/Dropbox/csharp/Reloaded/HelloWorld/bin/Debug/netcoreapp3.1/HelloWorld.runtimeconfig.json file specifying the appropriate framework.

"""

In the command line I can run my project with "dotnet run". I noticed that the content of /mnt/UBUNTU_OPT/Dropbox/csharp/Reloaded/HelloWorld/bin/Debug/netcoreapp3.1 differs in the two cases.

dotnet run produces these files:

HelloWorld
HelloWorld.deps.json
HelloWorld.dll
HelloWorld.pdb
HelloWorld.runtimeconfig.dev.json
HelloWorld.runtimeconfig.json

While Rider's "Run Project" produces less:

HelloWorld
HelloWorld.dll
HelloWorld.pdb