I had the exact problem, and had 2 hours of work in before realizing that I couldn't save.
Installing Cakewalk Product Center got me far enough to try the Offline Activation. Under Help->Offline Activation, I exported a Activation request, then use the Offline Activation tool in Cakewak Product Center (lower left, under Sign Out in pic above) to process that file!!!!
Thanks @Stylus Pick for the pointer to CPC. I thought I was running the latest version, but was only running 07.2024