If youre not seeing the same problem after completing the conflict test, then you know the problem was with the plugins and/or theme you deactivated.
To figure out which plugin is causing the problem, reactivate your other plugins one by one, testing after each, until you find the one causing conflict. You can find a more detailed explanation on how to do a conflict testhere.
Please make sure you have a backup in place of your site and database. You could also consider using a service like Jetpack. If something goes wrong, its nice to know that you can restore your site to the previous state.