Our setup is as follows: Site0: Exch00 - Original On-Prem Exchange server. CAS, MBX, and all transport roles. Was not configured to perform any hybrid/management work with 365. DC0 - Site local DC to site where Exch00 is
Site1: Exch01 - Hybrid server, all 365 management etc. MBX, CAS, contains resource mailboxes and mailboxes to be exported to PST or migrated to 365. DC1 - Site local DC for Exch01 Client computers
Sites2-5: client computers, local DCs.
External sites: lots of offices that are not AD integrated and are using Outlook Anywhere.
365 - Setup with dirsync, not ADFS
Site 0 has failed, and does not need to be recovered. All user and resource mailboxes and other user data that was needed has already been migrated from those servers, and the site was set to be decommissioned properly at the end of the month. However, a hardware failure has taken care of that for us. We can restore from backup if needed, but since we're just going to be restoring to decommission I'd rather avoid that if possible.
We are currently having issues with Equipment calendars (but not Rooms) not being available. They are all stored in the same database, on the same server. All other calendars are functioning properly, it's just Equipment mailboxes which aren't working.
In Site1 Outlook is prompting for a password constantly but is functioning regardless of if the password is entered or not. Users in the external sites are not experiencing this issue.
Prior to the hardware failure last night, everything was working properly even though all Exchange services were disabled on Exch00. The DC has already been removed from AD Topology via ADSIedit, and there are no traces of it in our KCC. The site still exists in ADS&S I have the following questions:
Can I remove all traces of Exch00 via ADSIedit, as I would any other failed Exchange server, or are there additional concerns because of the 365 tie in?
Is there a separate arbitration mailbox that's used for Equipment mailboxes than there is for Rooms? If so, is there a proper process for recreating this arbitration mailbox? If not, is it likely that the problems with the Equipment mailboxes will be resolved once Exchange has updated topology information?
What could be causing the Outlook password prompting? The DC in Site1 is fully functional as is Exch01. Sites2-5 are also having the same password prompting issue.
Remove the defunct Exchange server using ADSIedit. As long as you didn't include the server as an endpoint when you ran the Hybrid Wizard you are fine. If there is any concerns there at all - rerun the wizard afterwards.
I'm not completely sure on that one.
Outlook/Prompts:
First thing I would do here is find a user with this problem and check the connections Outlook is trying to make. It may help to run a tool like WireShark just to see what you are sending / receiving. This will tell you 100% where those Auth requests are coming from.