add a new trusted Master Server

Hello,

We are running 2 appliances hat function as master server.

I want to configure AIR between tham but when I tried to add a trusted master server I get the next error:

" Could not establish secure connection trusted master server. The remote master server may not be running NetBackup version 7.6 higher(5614) "

Important to mention that both of appliances with netbackup version of 7.6.0.4