Thank you for posting your question in the Microsoft Q&A forum.
Based on your description, I would like to share some information from my research and from Q&A Assist's recommendation that I hope will be helpful.
Update the Saved Contact
- Open Outlook and click on the People (or Contacts) icon (usually located at the bottom left or on the far-left navigation bar).
- In the search bar, type the name of the person > Double-click the person's name in the results list to open their Contact Card.
- Locate the E-mail field, delete the incorrect address, and type the correct one > Click Save & Close in the top-left corner.
Clear the "Auto-Complete" Cache
Even after saving the new contact, Outlook remembers the addresses you have used recently to help you type faster. You should delete the old memory. You can go to your Mail view and click New Email > In the To... field, start typing the person's name just as you usually would. When the list of suggestions pops up, look for the entry with the incorrect email address. Hover your mouse over that suggestion and click the X that appears to the right of the name and type the full email address manually one time. Outlook will save this new, correct address for future use.
Additionally, since this is a generic Business account, please note:
- If this is an external contact: The steps above will work perfectly.
- If this is an internal contact: You usually cannot change the email address of a fellow employee yourself. Internal contact information is managed by your company's IT administrator via the Global Address List (GAL). If a coworker’s email is wrong, please contact your internal IT Helpdesk to have it updated on the server.
I hope this information proves helpful!
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