Thank you.
I was finally able to resolve the issue. After doing a ton of reading, it seemed like others who have had the problem have been dealing with a possible hacking. the .php file listed as an error wasn’t in the original plugin package.
I deleted the .php file that was appearing in the error message. After deleting that, a new error message appeared when I refreshed the main page. I deleted that .php file as well, and the site has been working fine again. I hope this helps anyone else who has a similar problem.
