error message :
Your backup failed, and we were unable to detect any fatal errors. This usually happens when your hosting provider kills a backup process using the “SIGKILL” signal. To learn more about this as well as troubleshooting techniques, please click here.
To summarize the article, here are the most common ways to fix this:
Navigate to Total Upkeep > Settings > Backup Process. If System Zip is available, choose that option.
In the same menu, check the box to enable the Filelist Analysis and attempt to create another backup. Then, navigate to Total Upkeep > Tools > Logs, and look for the most recent log that ends in filelist.log. Examine the filelist and look for any very large files or directories. You can then delete those files if you don’t need them, or exclude them from your backups to conserve resources.