Are you using Outlook desktop client? If so, please make sure you have upgraded your Outlook to the latest version.
What's the type of your account? POP, IMAP or Exchange?
Despite being logged in, your password reset facility says my ID does not exist. I cannot send emails using Outlook.
Where does your email go to after editing and clicking send? Outbox or Sent Items?
To confirm if your issue is related to your Outlook client, please log in to your webmail and send the same test email to see if your issue could be reproduced.
If they can all work fine on the web mail, I'm afraid that your issue might be related to your Outlook client. Please follow the suggestions below to troubleshot:
- There might be something wrong with your email account in Outlook client. It is suggested to remove your email account and re-add it manually to your Outlook client to see if the issue has any difference.
- If the send/receive file (.srs) of your account is corrupted, it will cause issues like this. Please try to rename your .srs file and restart outlook client to test. Send/Receive FileLocation: drive:\Users\<username>\AppData\Roaming\Microsoft\Outlook
- A corrupted profile can lead this issue, so please try creating and using a new Outlook profile via Control Panel > Mail > Show profile and see if it works.