Note: I also tried all the fixes like changing this parameters
upload_max_filesize – set this to a value > than your backup
post_max_size – set this to a value > than your backup
memory_limit – set this to a value > than your backup
max_execution_time – set this to 0 (infinite)
Inspecting error logs (no errors).
The additional problem is also that I cannot get another site-backup without plugins since my subscription is deactivated and they say there is no files on server.