I had an old RubyMine 7.1.4 in Windows and installed new Ruby (3.0.2p107 (2021-07-07 revision 0db68f0233) [x64-mingw32]) with Rails (6.1.4.1) after uninstalling the old Ruby completely.
I configured path to Ruby SDK. RubyMine detected it without any problems.
Then I selected "Use other SDK" and the desired SDK in project options.
Now when I run any of project configurations I get an error:
No Rails found in SDK
although I can run the application using rails server
without any problems.
I checked many forums and none of the solutions worked, even those on Stackoverfow.
So I suppose, there is a general incompatibility of old RubyMine and new Ruby. Any chance to make them work together or I should spend money on the new RunyMine?