We sent an email to our email list containing multiple different URLs that ended in a closed parentheses )
The URL is correct in the builder and when we sent a test. However, when we officially sent the email to our list, the URLs were all missing the ) at the end.
This caused our links to spin endlessly and not load properly for our recipients.
What would cause this and how do we prevent this from happening in the future?
Try encoding the open and close parentheses as url safe instead. %28 for open and %29 for close. Also create an email test list (it's a specific function that renders the email in the way an actual recipient would receive it and not as the "test" function does. This is as good method to test such links as they would "really" be received.