These can look scary but usually are not hard to resolve. The key is finding the location of the error. By looking at the path of the error we can determine the location of the error. First things first, let’s enable debugging (don’t forget to turn this off.). Connect with FTP and edit the wp-config.php file, locate this bit of code:
and update it to:
Now we can locate the errors in our site.
The location of this error is
This error specficically states that the error is located in the plugins folder
And more specifically, even notes which plugin is the issue.
Contact form builder in this case.
The fix, connect with FTP, navigate to the offending plugin folder (path is in the error) and rename the folder to plugin-name.bak. If more than one plugin is displaying an error you can rename the plugins folder and disable all plugins at once.
Here is another quick example of a fatal error, but this one is the theme. Same renaming rules apply here too.