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Likely fix

Fix: Outlook app not sending on phone

The Outlook mobile app may not send because of connection problems, a stuck outbox, large attachment, account sign-in issue, sync problem, or app bug.

Quick answer

Switch between WiFi and mobile data, check the outbox, remove large attachments, restart Outlook, and update the app.

Important warning

Work or school accounts may have mobile device policies that affect sending or attachment behavior.

Try this

  1. 1 Switch between WiFi and mobile data.
  2. 2 Open the Outlook app outbox if available.
  3. 3 Remove large attachments from stuck messages.
  4. 4 Restart the Outlook app.
  5. 5 Restart the phone.
  6. 6 Update the Outlook app.
  7. 7 Check whether the account needs you to sign in again.
  8. 8 Remove and re-add the account if sending keeps failing.

Common causes

Bad network connection.

Stuck outbox message.

Large attachment.

Account needs sign-in.

App sync problem.

Work or school policy restriction.

What to check next

  • Check whether it sends on mobile data.
  • Check whether Outlook asks you to sign in.
  • Check whether webmail sends from the same account.
  • Check whether a no-attachment message sends.
  • Check whether the Outlook app needs an update.

FAQ

Why is Outlook mobile not sending?

The app may have a connection problem, stuck outbox message, large attachment, account sign-in issue, or sync problem.

Can mobile data fix Outlook sending?

Switching between WiFi and mobile data can show whether the current network is blocking or failing.

Should I remove and re-add the Outlook account?

Use that as a later step if restarting, updating, and checking the outbox do not work.

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Fix: Email won’t send with attachment

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Fix: Gmail not sending in browser

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