Hi @eg1995 ,
- If you send email in outlook, when the Autocomplete feature tries to input the recipient name or address for you, manually click the "X" to delete the entry, and then manually type the whole email address again.
- You also could add a X.500 email address for user. Please follow the steps:
- You could follow the method in the second link provide by AshokM-8240 to get the actual X.500 address.
- Open the EAC and select the user mailbox which email address has issue.
- Click the edit , then you could add X.500 email address on the email address page.
- Then try to send an email again and see if the issue is resolved.
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