Email stuck in the Outbox in classic Outlook for Windows?

Look in Sent Items for the message before making a copy or resending. If Outlook shows Disconnected, check your connection and try sending a small test message in your provider’s webmail with the same account. If webmail cannot send either, check the account or service first. The Work Offline ribbon steps here apply to classic Outlook for Windows.

Select Send/Receive → Work Offline to pause sending, then drag the oldest stuck message from Outbox to Drafts. If Outlook says it is already sending the item, close Outlook normally and retry after reopening. Open the draft and replace the large attachment with a smaller file or a sharing link the intended recipient can access. Attachment limits depend on the provider and account.

Turn off Work Offline, confirm Outlook is online, and send the edited draft. Check that it leaves Outbox and appears in Sent Items. If messages consistently leave only when you run Send/Receive by hand, look under File → Options → Advanced for Send immediately when connected. If a managed account locks that setting, ask your mail administrator.