Hi @radzimaphoto
This error means that while creating the backup, it exceeded the amount of memory that PHP is allowed to use.
Specifically, the error points out that it is already using about 66MB of memory, but failed to allocate about 726MB more.
There are a couple ways you can help fix this. First, check your PHP Memory Limit. You can find this in Tools > Site Health > Info > Server.
You can usually increase the PHP Memory Limit via your host’s control panel. For example, in cPanel servers you can find this setting in the MultiPHP INI Editor tool.
You may also be able to reduce the amount of memory required by switching your backup compressor to SystemZip instead of PHP Zip. Navigate to Total Upkeep > Settings > Backup Process and use the drop-down menu to switch the compressor.
While you’re on this menu, consider enabling the Filelist Analysis. This will provide you with information in your backup logs that may explain why the backup is using so much memory- if very large files are being compressed for example, or if another plugin’s backups are being backed-up. You can find your backup logs in Total Upkeep > Tools > Logs