HTTP Error 500 After logging into EAC (Exchange 2019)

Question

Hi,

I Can't log into Exch. 2019 EAC as a domain admin (or as nothing else).
The login screen appears correctly, but after logging in: This Page isn't working, localhost unable to handle this request. HTTP error 500.

What I tried so far:

• Setting a wildcard certificate for default website and for exchange backend in IIS.
• • Checked if the Computer that hosts Exch2019 is in a group denied on ms-Exch-EPI-Token-Serialization as it detailed here:
• https://learn.microsoft.com/en-us/exchange/troubleshoot/client-connectivity/error-occur-ems-eac-owa it is not.
• • Succesfully ran these two powershell scripts: updatecas.ps1 and updateconfig files.ps1 in here.C:\Program Files\Microsoft\Exchange Server\V15\Bin
• • In exchange management shell, removed and recreated OWA virtual directory.
• • Installed all pending updates on winserver 2019.

Note that a few days ago we removed the hybrid configuration from the organization since we have an Exch. 2013 in the org. as well, which we want to decomission and keep only Exch2019 as Microsoft reccommends for management purposes only. Is it possibe that removing Hybrid configuration caused the error?

I am out of Ideas, maybe I can re-run exchange setup, but I am afraid it removes already created O365 mailboxes (with dir synchronization from local Ad)

Any help appreciated, thank you.

Answer 1

Did you move the arbitration mailboxes to the 2019 server?

If not, they need need to be recreated. this wont remove any 365 mailboxes

https://learn.microsoft.com/en-us/exchange/architecture/mailbox-servers/recreate-arbitration-mailboxes?view=exchserver-2019

Setup.exe /PrepareAD

Answer 2

Thanks for replying,

We tried to move the Arb. mailbox, to the Exch2019 database, but it failed with an error. Then we tried to disable it, but that failed too. This was after we removed Hybrid configuration.
With this in mind, should I recreate it in Exch2019?
Thank you!

Answer 3

I found another error in the logs that is maybe the root cause of the problem:

ID: 4 Source: MSexchange Control panel:

Current user: 'contoso.com/Microsoft Exchange System Objects/Monitoring Mailboxes/HealthMailboxe834d40c01854fc18114798860aaedc5'
Request for URL 'https://localhost:444/ecp/About.aspx' failed with the following error:
System.Web.HttpUnhandledException (0x80004005): Exception of type 'System.Web.HttpUnhandledException' was thrown. ---> Microsoft.Exchange.Data.Directory.ADTransientException: Could not find any available Global Catalog in forest contoso.com