Square Payment Module for Zen Cart [Support Thread]

[DrByte]

After ... putting a replacement cacert.pem file in the PHP environment, and upgrading the site to 5.6 the test script was able to run completely.

Once curl would work correctly the green button acted as it should and Square was active on the site.

Excellent. Glad the curl issue is sorted. And the SSL.

... go through the checkout process until I get to the confirm my order where after I push the button it waits for a minute or two and then gives me a 500 - internal server error.

In web terms, a "500 Internal Server Error" is a general message that's generic publicly because being more specific could put your site at risk. The actual system details that caused the issue will be found in server logs. If the problem occurred at the Zen Cart level, then it will be logged in the /logs directory as myDebug-xxxxxx.log files. Will need to see those messages to understand better what's up.