'too many installs'!

Hi Antoine - I purchased a lifetime licence back in December 2017, when I had a Mac laptop only. Since then I’ve updated to 3.5 and installed on one other Mac (a 2014 Mac mini). Now I have a new computer and the old 2014 mini is dead & won’t boot, so I can’t revoke etc. I want to instal on the new Mac but ‘too many installs’!
Is there any way you can fix this at your end or is there something I can do at mine?

Hope all’s well & safe,

Peter Fairbairn