Hi @Melvin Sakurai ,
Did this issue occur on this POP account only? Would this issue be reproduced on your Outlook if you re-configure this account with imap or configure other pop account there?
I noticed that you are working with a third-party antivirus software, in order to avoid the interference of it, it's recommended to close it temporarily to check if you could send/receive normally in this case.
If the issue still exists, based on my research, corrupted Outlook data file may also cause it, please try to repair your Outlook data file to check.
If that also couldn't work, it's suggested to create a new Outlook profile for testingControl Panel>Mails >Show profiles>Add>readd your account).
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