@OMADA-tunisia 

that could be normal behaviour so that the Omada app can access the database tables and dump them to a file.  The more stored info you want to save, the longer the timeout should be.  My guess is your controller is alive and well, just paused while it copies data (it's hard to dump a database table that can be restored successfully if you allow read/writes during the time you back it up...so most will lock the database table while it dumps...and this will cause your UI to freeze because it's heavily dependent on data coming in from the database).

I'm sure if you run a ping -t ip.addr.of.oc200 while you do this, the pings will continue, it's just the UI that freezes.

  @OMADA-tunisia 

Are you storing the file locally, or to an offboard filesystem?  Do you have enough space to store the backup?  check the Settings->Controller->Maintenance menu:

Ensure you have sufficient internal storage remaining for another backup.

OMADA-tunisia wrote

I'm getting problem when performing backup on oc 200 when shoose any option beside setting back up. The oc 200 disconnect and stop responding and it will reconnect after 1 minute or so

Dear  @OMADA-tunisia 

To assist you efficiently, I've forwarded your case to the TP-Link support team who will contact you with your registered email address later.

Please pay attention to the email box for follow-up. Thank you so much for your cooperation and patience.

Dear @OMADA-tunisia ，

Hope you are doing well. I’m wondering whether your concern was resolved finally?

If the issue still exists, please don't hesitate to reply to the support email who case ID is TKID220513279 for further follow-up.

If your concern was resolved, welcome to update this topic thread and share your solution so that others may benefit from it.

We are looking forward to hearing from you again.