No valid license issue

Hi, hope someone can help with this. I need to open some old projects mixed on N4 on my old Imac running on El Capitan; but since I upgraded to N11 (which obviously I use on a more updated mac) my elicenser shows no valid license (says “unknown application”) when I try to launch N4 (on the old Imac of course).
My elicenser version is 6.12.8.3306
Anyway I can get around this?
thanks

What does the maintenance task show as the result?

If your installation on a different machine is working, there should be a license available.

I didnt run the maintenance task on the El Capitan Imac because I didnt want to risk messing around with the elicenser; do you think I should try?
doing maintenance on El Capitan wouldnt cause any problem to my N11 license?