Hi Aniya,
So sorry for the delay. We thank you for reaching out with your Total Upkeep questions!
This error is likely related to file permissions on your server. Normally when you see this it means your System Administrator disabled write permissions on the root of your website, and only allows the user to write to the wp-content directory rather than the core WordPress files.
It might help for us to view your restoration log. Navigate to Total Upkeep > Tools > Logs and locate the log file called restore-XXXXXXX.log
with a timestamp that corresponds to the failed restoration, and copy and paste any errors in that log here so we can dig deeper for you.
We look forward to hearing from you!