Hi,@Kranthi
Thanks for posting your question in the Microsoft Q&A forum.
If the mobile phone is unable to contact the Exchange server automatically through the Autodiscover service, you'll need to set up the mobile phone manually. Manual setup requires the user's email address and password, as well as the Exchange ActiveSync server name.
You can refer to this link for details:https://learn.microsoft.com/en-us/exchange/clients/exchange-activesync/configure-email-access?view=exchserver-2019&source=recommendations
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