Managed to find a solution (hopefully a permanent one!)
I disabled Groupy, launched the file and saved it. Then I restarted Groupy and opened the powerpoint file./
It works.
There is a chance the problem is due to files created in a previous version of Powerpoint as compared to the one being used.
I will try with Excel now.
On a separate note:
Quick question with regards to licensing: I noticed the license is annual .
Can I still use my add-ons after the 1 year mark (minus support/updates) or the license key will be disabled and they will stop working?
Thanks!!