Make sure that any of following function is enabled at your server (Most server support any of this function)
- PHP proc_open and shell_exec function
- Zip Archive function
- PCL ZIP function
Also make sure that you have either MYSQL DUMP is enabled at your server.
If you have large site, make sure you have option 1 Proc_open and shell_exec function works at your server, this method runs for longer time instead of php zip methods that get timed out in 30 mins (depend on execution time)