OTD and Exchange on-prem - "Calendar access not permitted"
Customer is trying to test OTD service. Integrated with Exchange on-prem, version 2016
Service account is created according to guide, integration between OTD and Exchange is done and OTD is showing that it is integrated. Service account is set to have rights "Reviewer" to mailbox accounts. Device account is configured as Room Resource and has configuration done with Set-CalendarProcessing as needed.
Now, when trying to integrate Group Series device with OTD - it shows for some time error about wrong domain, username or password, then after some time device shows in OTD but with error "Calendar access not permitted".
OTD help is not very useful here, just saying "The service account used to integrate this calendar with One Touch Dial does not have permissions to access the calendar. Update the permissions of the service account used to integrate the calendar with the One Touch Dial application."
As I said, service account has Reviewer rights and that was double checked.
Now one interesting thing is - if they change that account to standard User, not Resource, then OTD is quickly showing that Calendar is connected. But still, no matter what configuration - Group is not showing any meeting notification, when Calendaring service is set to otd.plcm.vc.