Help licensing older version

Just curious if anyone has some tips on troubleshooting the licensing process.  I have a license I paid for the 20.00 version around 2018.  I've switched to an M1 Mac and am running Parallels with an ARM preview version of Windows 10 and the latest Excel.  When I try to type in the registration details the Registration window hangs (not responding) and Excel quits and it does not register it.  Any tips?