It seems that there is a conflict with your plugins. That’s why, you are seeing this blank page. Follow these steps to solve the issue:
- Purge the cache content of your cache plugin or server cache.
- Deactivate all the plugins. Then reactivate them one by one. In this
way, you can find the defective one, which you have to replace with
an alternative option. - Clear your browser history. Then head to Appearance > Menu. You
will find that the issue has been fixed.