Using Classic Outlook on Windows for personal email, calendar, and contact management
I understand how inconvenient it can be to repeatedly receive an invalid certificate warning while setting up a new account in Outlook.
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Since you removed the previous account, please try creating a new Outlook profile:
- Close Outlook.
- Open Control Panel, then select Mail.
- Select Show Profiles > Add.
- Enter a name for the new profile and add your email account.
- Select Prompt for a profile to be used, reopen Outlook, and choose the new profile.
If the warning continues, do not accept or install the certificate until it has been verified. Check whether the certificate is expired, untrusted, or does not match the mail server name.
If you are adding an Outlook.com or Hotmail.com account, please contact Microsoft Support. If you are adding a Gmail, Yahoo, or custom-domain email account, contact the relevant email provider or system administrator to verify the mail server settings and certificate configuration.
Please feel free to let me know if you have any further updates, thanks.
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