Hi.
It looks the Session Manager is triggering a backup but the Oracle Agent doesn't connect back in 10 minutes, leading to a failure. On the Oracle side, the problem seems to be that the agent can't find the cell manager to connect to. It would be best to double check your client's configuration, and if nothing can be found to be at fault, to create debugs and get in touch with your support contact.
Regards,
Shishir