No error message is seen in the Job List of O365 Sync. On the contrary, the sync shows as a Success, however no records are found to sync.

Microsoft plans to deprecate Exchange Online Remote Powershell(RPS), as its a legacy technology that is outdated and recommends all O365 to use REST-based v3 PowerShell module. If a connection attempt is made from a lower version of Exchange Online Management PowerShell module to a tenant for which RPS is disabled, then O365 Sync is unable to fetch data for sync.
Veritas is working on upgrading the PowerShell module on all Data Centers to v3. Until this is deployed, customers can request Microsoft to enable RPS on their O365 tenant by following steps from the below link:
Diag: Enable RPS in EXO
Microsoft KB Article covering more information on this topic:
Deprecation of Remote PowerShell in Exchange Online – Re-enabling or Extending RPS support