Outlook permanent Prompting - Outlook not able to connect to Exchange on Prem aynmore

Fabio Scarvaglieri 1

Hi all togehter,

having an Exchange 2019 on prem.

Our Outlooks are not able to connect anymore to our Exchange Server.

The Cert is valid, it includes all domainname and autodiscover.ourdomain.com
Connectivity Tests like:
https://testconnectivity.microsoft.com/result/d80c0541-286b-3fb6-3e3a-0fc39d56c660
are working well.

OWA is working absolutley perfect, no cert errors, no login issues.
Apps like Apple Mail, or Android Mail Apps are working and synching well.

The Only thing is that Outlook Asking ALLWAYS for credentials, and is not able to establish a connection.

Of course Username and Password is 100% typed correctly.
This happens on all Outlook clients within and from outside our org.
Tried on new Computers... all behave the same.

We're Having latest Outlook Clients from O365 Subscription.

I would appreciate any Help on this.

Who can give some HINTS where the Issue could be ?

thanks in adavance
Fabio

Aaron Xue-MSFT 2,581 Reputation points Microsoft Vendor

2021-11-03T07:43:09.367+00:00

Hi @FabioScarvaglieri-9149
Do you mean that you can connect to owa but unable to outlook?
According to your Information. Please to use the Test-Email Autoconfiguration option to check the process of autodiscover in outlook.
1.Hold the Ctrl key and right-click the outlook icon, and select “Test Email Autoconfiguration”

2.Input your email address and password. Only select “Use Autodiscover”. Then click “Test”.

3.After the test completes, check the result under the “Log” tag. Please remove your personal information then share a screenshot here..
Aaron Xue-MSFT 2,581 Reputation points Microsoft Vendor

2021-11-08T09:51:14.627+00:00

HI @FabioScarvaglieri-9149
Did the issue get resolved?
If you have any questions or need further assistance, please feel free to post back.