You could try testing for a plugin conflict first. You can do this by deactivating all third party plugins, and seeing if the problem remains. If it's fixed, you'll know a plugin caused the problem, and you can narrow down which one by reactivating them one at a time.
If the issue persists after that, would you mind providing us with login credentials so we can take a closer look? Please provide following information:
Set it as Secure Note
- Link to your site
- WordPress Admin username / password
- FTP credentials
All the best!