Hi @BAB ,
Does the Outlook client keep prompting for a password?
If in this case, the issue may occur with Outlook bypasses local autodiscover and directly connects to Office365.
You could follow the steps to create ExcludeExplicitO365Endpoint registry value to bypass connection to O365.
1.Press win+r, then type regedit on the outlook client.
Find the below path.
HKEY_CURRENT_USER\Software \Microsoft\Office\16.0\Outlook\AutoDiscover
If you do not have the AutoDiscover key, please create it under the HKEY_CURRENT_USER\Software \Microsoft\Office\16.0\Outlook
2.Create a new DWORD parameter named ExcludeExplicitO365Endpoint and value 1 , then restart Outlook.
3.Check if the issue persists.
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