Hi, @kdobbe12.
Glad you reached out.
The first thing I suggest here is that you restore a backup of your site so you can accept donations on it while we investigate the issue.
Then, on a staging site, you will update GiveWP, its add-ons and any other plugins you have to the latest version.
A staging site is an exact copy of your live site, but that is hidden from other users and that people use to test things before modifying the live site. Creating a staging site may not be easy, so your hosting company will be able to help you with that since they have access to your server and site.
Then, on the staging site, you will check if you can still make donations after you update everything. If you can’t, let us know. And if you get a critical error like that, typically, this error means some broken code is causing your site to crash. It is a WordPress system-generated message that means something has caused a PHP fatal error.
Whenever you see that message, a more detailed error log has been sent to the main admin email address (which you can configure at Settings > General in the main WordPress settings).
Check that email, and then pass along any error messages you are receiving so we can help. Every time you see that error, it sends another email. If you need to, you can trigger a new email to be able to see the error message again.
If you don’t see that error in your email (WordPress emails are notoriously unreliable that way), you’ll need to ask your host for the error logs. They will be able to send you a complete record of the errors on your site. Once they provide you with this file, send it to us, and we will be able to identify the issue and move toward a resolution for you.
Your success with online donations is our number one priority. Looking forward to helping you get to the bottom of this!