I installed the patch from the thread https://www.joomlart.com/forums/d/22933-registrations-dont-work/16 and a new issue - errors when going to the payment page - started. My post from that thread:
I've applied the change and get a new error. In Chrome it reads:
This page isn’t working www.mywebsite.com redirected you too many times.
Try clearing your cookies.
In Microsoft Edge it reads:
Hmmm...can’t reach this page
Make sure you’ve got the right web address: https://www.mywebsite.com
Search for "https://www.mywebsite.com" on Bing
Refresh the page
There were too many redirections.
Error Code: INET_E_REDIRECT_FAILED
Internet Explorer just hangs when I click "Next Step".
I normally use Chrome, and only for error testing (like this) do I ever use Edge or IE. This error occurs on an Individual registration on the "Please check the data below..." page.
Group registration gets me to the billing contact page, but fails when I go on to payment (yes, I did install and configure the latest version of JA Payments).
So it appears the payment page is what's failing now.
Note that this website I'm referring to is in a subfolder of the public_html folder indicated in the credentials provided. Please do not touch the root Joomla install - that is another site.