In case it doesnt work for you:
Problem Clarification
Error message when trying to enable the "Force Phones and Gateways to Active LSPs" option: All MGs with the same backup server must have the same recovery rule
Cause
The ‘immediate’ return to primary server option in the media gateway recover rule is not usable along with the "Force Phones and Gateways to Active LSPs" option. This option is in lieu of using an existing media gateway recovery rule administered for 'immediate' return to the main, which can be found on the SAT's SYSTEM PARAMETERS MEDIA GATEWAY AUTOMATIC RECOVERY RULE screen.
The return to main server options that can be used with the "Force Phones and Gateways to Active LSPs" option are as follows.
1. Time-day-window.
2. The enable mg-return command.
3. Return to the main server if an LSP is unregistered.
Another issue might be if a MG is set to a NR where the the backup server is not set.
You have to have a backup server set on the NR that conins MG's or you need to disbale the Recovery Rule on those MG's
We have an official guide which explains this feature in very details.
You can download it here:
Solution
Do not use the ‘immediate’ return to primary server option in the media gateway recover rule along with this feature.
AND/OR
Fill in the BACKUP SERVER field, or set Recovery rule to none
Let me know if this helped or not.