if the site is very large, it takes time to create the backup. And if the server execution time is set to low value, you get go to blank page. There may be chance your server max execution time is 30 second. Please check debug log file. You will need to ask your hosting services to increase the execution time and the plugin will work fine for large data. You can also try to increase execution time. Please make below changes – Add below line
max_execution_time = 180 ;
Also Please make sure that you have write permission to Backup folder and also check your log file.