mu-plugins causing error on site

Hey all!

Out of no where, my website was popping up with an error and would not let me login to the back end. My host support was able to figure what was going on and said there was an issue with the mu-plugins file.

I am not an expert developer and this has never happened to before with any of my sites i have built. With the help of support, they have helped me locate and rename the file to mu-plugins_old which they have said will disable all must used plugins.

I can now access the back end of the website but I am worried that if all must used plugins are disbled – this would effect the functionality of the site?

Any help or advice on how to fix this error properly?

thanks!

The page I need help with: [log in to see the link]