my outlook has stopped sending emails. They are locked in the outbox. I am receiving emails perfectly normally.

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Hi John Bambery

May I ask if you are using Exchange, IMAP or POP account?If you are using Exchange, please log in via https://outlook.cloud.microsoft/mail/ and check if you can send new emails there.

If you are using IMAP or POP, verify your SMTP port and server name. If possible, can you please provide your provider's name so I can find more information about it.

You mentioned you spoke with Microsoft Support about using New Outlook? Did he mention what issue in particularly?

When you log in with New Outlook, does any error message show up? If yes, please provide it.

Additionally, if you are using a business account, an IT admin of your organization can block users from using New Outlook. Control Installing and Using New Outlook | Microsoft Learn. So please check with your IT admin as well.

Some of the basic method you can try is:

• Remove and re-add account.
• Open Outlook in safe mode - Microsoft Support (If this works, the problem is likely one of the add-ins, you can go to File > Option > Add-ins > Go > Uncheck any suspicious add-ins)
• Rebuild .ost file: Close Outlook > Press Windows + R > Type in %LOCALAPPDATA%\Microsoft\Outlook\ > Look for your email address and delete it > Restart Outlook. (Applies to Exchange and IMAP accounts only)

Please provide more information so I can assist you better. I look forward for your reply.

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