Diagnosing "An error occurred while processing your request"

We’re in the process of upgrading the Gravity Forms Square add-on, and after upgrading to v1.7 we are seeing an issue where the card details field is just outputting the message:

“An error occurred while processing your request, please try again later.”

I’ve done some digging in the ‘class-gf-square.php’ file where the error strings are defined, and there are a few cases where this catch all error is used. Does anyone have any insight on diagnosing this issue? There isn’t anything being sent to the logs that I can see.