Exchange specific account cannot log in to the mobile Outlook app

Question

As the question suggests, the account can be logged in and used normally in both web and PC Outlook, but cannot be added to the Outlook app for login on the mobile end. Exchange is the 2016 version. I have conducted some checks and checked the logs as follows:

Please help analyze and solve it, thank you.

Answer 1

Hi @功 陈,

Welcome to our Q&A forum!

Regarding your issue, EventID4625 is a general user account audit event. This event generates if an account logon attempt failed when the account was already locked out. It also generates for a logon attempt after which the account was locked out.

Based on my search, there could be several reasons why the ActiveSync connectivity test failed. One possible reason could be that the server address and Domain\Username were not input correctly during setup. Another reason could be that the Outlook mobile app is not up-to-date.

If you would like to try some quick fixes, you can try the following:

1. Check Active Directory permissions for the user: https://learn.microsoft.com/en-us/exchange/troubleshoot/client-connectivity/troubleshoot-activesync-with-exchange-server#check-active-directory-permissions
2. Confirm that ActiveSync is enabled for the user in EAC:
3. Confirm that the mobile device isn't blocked by an ActiveSync quarantine rule.
4. Stop all firewall setup and check server network connections, then restart the ActiveSync service.

More detailed steps about troubleshooting Mobile ActiveSync you can refer to : https://learn.microsoft.com/en-us/exchange/troubleshoot/administration/mobile-device-cannot-connect-via-activesync#resolution---step-1-confirm-that-activesync-is-enabled-for-the-user

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