It's because your account was deleted. When the accounts recover from the Johnny crash, it only comes back with whatever main domain you pick. I've added mydigitallife.tk back to the account for you. It should work within 2 hours.
Free subdomains ending in heliohost.org are no longer available to users, and have been restricted to system functions and staff accounts for several years now. It's just that a few users like you have been here so long that they still had them on legacy accounts. I've temporarily added it back, but it will redirect users to astron.helioho.st when they visit it so bookmarks and search results for your old domain can find the new one. There will be a point where the .org domain stops working, so please notify your users. It can take up to 2 hours to function.
You have to unpack that on your PC and manually restore the files. You can't use the built-in Plesk restore function to restore it. Depending on the format, it's either a plain tar.gz archive containing a copy of your home folder, or a plesk backup (which can unpacked using these instructions: https://wiki.helionet.org/Account_Backups#How_to_Extract_Your_Account_Data_from_the_Backup_File)