Broken Calendar Assistant

Question

Hello,

I currently have an issue with the Calendar Assistant in Exch 2016. The assistant is instantly failing when trying to pull the calendar of anyone with the DB mounted on this server. As soon as I push the mounted DB over to the 2nd server in the DAG it works perfectly. They are replicated copies of each other. Anyone seen this?

Environment setup:
Exch 2016 on premise - 5 Server DAG on CU19
*Server 1 - Inbox/Calendar - "Healthy" DB 01/03 (Currently hosting a test database and 1 user for troubleshooting this issue)
*Server 2 - Inbox/Calendar - DB 02/04 (Currently mounted all 4 DBs)
*Server 3 - Public Folders/Journaling - Mounted DBs for both.
*Server 4 - Public Folders/Journaling - Healthy Replicated/Copy of PF and Journaling.
*Server 5 - Witness

Tried so far:
Recycled MSExchangeAutodiscoverAppPool
Recycled MSExchangeServicesAppPool
Created the Test database and a test user and mounted it to the affected server for testing

Note that the Server 1 and 2 both have the same security updates etc. Nothing is different about them.

Answer 1

This turned out to be IISCRYPTO incorrectly changing the TLS 1.2 Enabled key to "FFFFFFF" instead of "1" in the registry. We are good to go!

Answer 2

Hi @Mike P

Thanks for the detailed information.

I would like to confirm with you:

1. Did you mean if the databases are active on Server 1, all users will be unable to see each other's free/busy information?
2. Does this problem occur on all internal and external clients?

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If it is the case, I suppose that the possible cause of the problem would be the EWS(Exchange Web Services) virtual directory, which is responsible for free/busy.

Please run a Test E-mail Autoconfiguration via Outlook client with the credentials of the test user on the affected server.
Check the results under the "Results" tag to see if the URL of Availability Service is returned correctly:

And check if it matches the internal or external URL settings of the EWS virtual directory on the affected server in EAC.

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