To ensure I understand, could you elaborate more on the issue? If you can phrase it in the “When A happens in Service X, B should happen in Service Y” format, that’ll help me make sure I give you the best suggestion possible.
Also, could you send screenshots of how you’ve configured the Zap so far? (If there’s any personal information, kindly blur them.)
I did some digging into this, and it seems like one user encountered a similar issue where Facebook required them to upgrade to the "New Pages Experience", causing some problems. However, they were able to connect their account successfully after downgrading to classic.
Additionally, I've seen similar connection issues with some of our customers using FB Lead Ads because the connection involves Business Manager as well. Should you wish to upgrade to the "New Pages Experience" here's what we look for to confirm all the permissions are in place:
The Facebook Page Owner needs to have a Business Manager account
If someone else, not the Owner, wants to connect with a Zap, they need to be added as "People" and with "Admin access" (this means they need to have a BM account as well)