Hi LT31860,
Thanks for reaching us in community!
May I know why type of connector were you trying to add? Is it a custom connector you developed? From my limited experience, I cannot find it in the connectors.
For such an error, I suggest checking your Teams apps permission polices in the Teams admin center first.
Make sure you have allowed all the apps, since from the error message it indicates a block.
Best,
Shawn