There will be code in the plug-ins that is not correct or is in conflict with other code in your plug-ins or themes. To fix this is not easy, since several people have all had the same issue, I suggest it is a plug-in code that is the problem.
You could de-activate your plug-ins one at the time and find the culprit
Or de-activate all of them and then re-activate one at the time until you find the rogue plug-in
Once the plug-ins are disabled your site should be back to normal.
It is time consuming
Or you can get in touch with your hosting company and get support to find out the problem.
Another solution is to remove the plug-ins. You can do via ftp or via cpanel. Suggest you do a complete backup first.
