Schedule assistant not working in OWA

I have updated my on-prem email servers from ex16 to ex19. I have three databases (DB01, DB02, DB03), so far I have test users on all three databases and both exchange environments are running. we discovered that users that are on DB01/DB02 (new environment-ex19) have the ability to use the schedule assistant in the calendar for both OWA and Outlook client; however users on DB03 can only use the schedule assistant in the calendar within Outlook client. OWA is blank and does not show anything. It all works fine in our ex16 environment.
I ran the following powershell command against one test user on DB03:
"Set-MailboxFolderPermission -Identity tuser1@fortluptonco.gov:\Calendar -User Default -AccessRights  AvailabilityOnly"
This seemed to allow the user to use the schedule assistant (Calendar) within both Outlook client and OWA but when I tried on tuser2, it still does not work in OWA.
Any assistance would be appreciated.
Thank you