After restarting services on the core servers like Primary /OC /CABI it is observed that there are no maintenance schedules defined in the schedules view in Operator console
When looking for a specific server in inventory the associated schedules are seen
At the database level, all maintenance schedules are seen
Also having issue to create new schedules from the groups menu in Operator console
Release : 20.3.x
Component :Operator Console
After reboot of the UIM servers the maintenance_mode probe took a higher port number like 48065
The port range between the Primary hub and OC servers were only opened in the 48000-48050 range
Due to this the OC was not able to communicate correctly with the maintenance mode probe
After opening additional range of ports on the firewall between the Primary hub and OC server the maintenance schedules are able to be retrieved successfully and populated in OC