Websites Down After ManageWP Backup & Update

I need urgent assistance. After performing backups and updates via ManageWP, several of my websites are no longer loading. When I attempt to access them, I'm met with a blank screen. There's no indication of an error during the backup or update process as everything appeared to be fine.

Ideal skills for this project include:
- Proficiency in troubleshooting website issues
- Experience with ManageWP
- Strong technical skills in web management and maintenance

Your expertise can help me resolve this issue as soon as possible.