This issue occurs since service which is responsible for taking scheduled backups "QuartzSetupServiceImpl" is down, so scheduled backups will not succeed.
If automatic backup is already scheduled in customer environment to check if Quartz service is running without any issue you should be able to see below logs in nsxapi.log for every 4 mins.
/var/log/proton# grep "Scheduler starting to create" nsxapi.log 20XX-XX-XXXXX:XX:XX.XXXX INFO scheduling-worker-1 InventoryBackupJob - - [nsx@6876 comp="nsx-manager" level="INFO" subcomp="manager"] Scheduler starting to create and upload inventory summary 20XX-XX-XXXXX:XX:XX.XXXX INFO scheduling-worker-1 InventoryBackupJob - - [nsx@6876 comp="nsx-manager" level="INFO" subcomp="manager"] Scheduler starting to create and upload inventory summary
NSXT> get cluster status verbose | find QuartzSetupServiceImpl QuartzSetupServiceImpl 0f2e2842-983a-f74b-77e2-e11156734de6 20163
NSXT> get cluster status Cluster Id: c7a0a122-54cc-4078-9297-4f40c45e0902 Overall Status: STABLE Group Type: DATASTORE Group Status: STABLE Members: UUID FQDN IP STATUS 0f2e2842-983a-f74b-77e2-e11156734de6 NSXT 10.172.78.76 UP
2. Once you have the leader manager details ssh to that manager with root account and restart Proton service in that manager using below command.
root@NSXT:~# /etc/init.d/proton restart