wp smush pro 500 error after switching servers from php5 to php7

When I run bulk smush, I get the following error: Error posting to API: 500 Internal Server Error1 image(s) were skipped due to an error.
It is not logging anything to my apache error log.
This is a new server running php7. We had it on a different server with php5 and it worked fine there.
I havent been able to test single file smush because everything I see just has smush stats already.
I can't give access and I can't disable other plugins, this is a live site. I'm hoping it is an easy fix you can tell me, otherwise I will have to spin up a clone to work on it.