Autodiscover issue internal server error occured Exchange 2019

Question

Autodiscover issue internal server error occured Exchange 2019

Jean-Marc Francois 41

We are migrating the current exchange 2013 to Exchange 2019. (OrgA)
This organization is sharing the same SMTP domain with another org (orgB) still in exchange 2013
They share their calendar so a FIMSYNC is in place that synchronize User from Exchange 2013 to contact in the Exchange 2019 organization.

We have a lot of error 1003 : [Autodiscover] An internal server error occurred. The unhandled exception was: System.InvalidCastException: Unable to cast object of type 'Microsoft.Exchange.Data.Directory.Recipient.ADContact' to type 'Microsoft.Exchange.Data.Directory.Recipient.ADUser'.

I think that it is the Exchange 2013 user from ORGB that are trying to contact the autodiscover service in ORGA and as their user is a contact we have this error. We never had such errors in Exchange 2013.

Is it possible to get more logs to troubleshoot the issue?

Thanks

Jean-marc

Kael Yao 37,746 Reputation points Moderator

2021-10-29T03:32:21.193+00:00

Hi Jean-marc,

I think that it is the Exchange 2013 user from ORGB that are trying to contact the autodiscover service in ORGA and as their user is a contact we have this error.

I also think the possible cause may be with autodiscover.

Have you modified the autodiscover DNS records to point to Exchange 2019 in public and internal DNS servers?

And does this issue only happen after a mailbox is migrated from Exchange 2013 to Exchange 2019?
If the mailbox is still on Exchange 2013, will the same issue occur?

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Kael Yao 37,746 Reputation points Moderator

2021-10-29T03:32:21.193+00:00

Hi Jean-marc,

I think that it is the Exchange 2013 user from ORGB that are trying to contact the autodiscover service in ORGA and as their user is a contact we have this error.

I also think the possible cause may be with autodiscover.

Have you modified the autodiscover DNS records to point to Exchange 2019 in public and internal DNS servers?

And does this issue only happen after a mailbox is migrated from Exchange 2013 to Exchange 2019?
If the mailbox is still on Exchange 2013, will the same issue occur?

Answer 1

Jean-Marc Francois 41

Autodiscover point to the Exchange 2019 servers. Exchange 2013 users in ORGA have no problems.

In ORGA there is no issue.

As the two organizations share the same SMTP domain, users in ORGB are connecting to autodiscover.SMTPDOMAIN that is hosted in ORGA. Then the corresponding contact has a target address that redirect to OrgB. But it is a contact and I suspect that Autodiscover in Exchange 2019 doesn't support that. So we have Unable to cast object of type 'Microsoft.Exchange.Data.Directory.Recipient.ADContact' to type 'Microsoft.Exchange.Data.Directory.Recipient.ADUser'.

Kael Yao 37,746 Reputation points Moderator

2021-11-03T09:20:02.083+00:00

Thanks for the information.

To my understanding, ORGB users are cross-forest contacts in ORGA.

Then the corresponding contact has a target address that redirect to OrgB.

I think this setting should work for mail flow but not for client access.
How did ORGB users connect to their mailboxes before you deploy Exchange 2019? Do you have other autodiscover domains and records to point to Exchange 2013 in ORGB?
Kael Yao 37,746 Reputation points Moderator

2021-11-08T09:26:27.78+00:00

Hi anonymous user

I am writing here to confirm with you how thing going now?
Did the issue get resolved?

Answer 2

Yaroslav Z 1

Hi there,

can you try to set attribute 'msExchVersion' value to 1125899906842624 on a cross-forest contact and check if the exception still occures?
We have a similar setup, and have issues with cross-forest sharing between Exchange users in the trusted forests.

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Autodiscover issue internal server error occured Exchange 2019

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