The customer was performing an upgrade on the device from 19.4R2 to 21.2R3. During the mastership switchover from the backup RE to the master RE, all interfaces went down.

We could observe from the interface terse output , all interfaces were down

Both RE were upgraded successfully , when mastership switch over was performed, we could observe all the interfaces showing down and unable to access the master RE via management interface.

Checked if license was installed post upgrade , in some cases for MX104 devices post upgrade 10G interfaces will be going down , need to install the license. In this case license was installed and we could observe the license keys. In order to bring the interface we tried to restart the MIC with the following command as FPC is built-in in MX104.

request chassis mic mic-slot 0 fpc-slot 0 offline

request chassis mic mic-slot 0 fpc-slot 0 online

After restarting the MIC. We could observe all the interfaces were up and stable.

We were able to login master RE via management interface as well.