The issue occurred because the solution user did not have the required permission and /var/log/vmware/vmware-updatemgr/vum-server/vmware-vum-server.log contains the error:
yyyy-dd-ddThh:mm:ss: info vmware-vum-server[xxxxx] [Originator@6876 sub=IntegrityAuthzServiceHelper] [AuthzServiceHelper 69] Entity PrivResult:PrivId:VcIntegrity.lifecycleSoftwareSpecification.Write,PrivValue:false
yyyy-dd-ddThh:mm:ss: info vmware-vum-server[xxxxx] [Originator@6876 sub=IntegrityAuthzServiceHelper] [AuthzServiceHelper 186] User: vpxd-solution [email protected] does not have Privilage: VcIntegrity.lifecycleSoftwareSpecification.Write on entity:domain-cxxxxxx