Error message: ENOTSUP

I am new to Julia. I am trying to add packages in JuliaPro. For example I do this:
using Pkg
and the following error message pops up:
ERROR: IOError: mkdir: operation not supported on socket (ENOTSUP)

My OS is MacOS Big SUR 11.2.2.

Could someone explain to me what is going on?
Many thanks!

Can you try using regular Julia instead of JuliaPro? Most people on here don’t use JuliaPro, so it’s easier for people to help if whatever goes wrong can be reproduced with standard Julia.

I also downloaded Julia and tried the same commands. The same error message pops up.