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Mac Mail not sending?

If emails sit in the Outbox or the Send button won't work, go through these checks from Apple's Mail help, roughly in order.

1. Check the connection

Make sure your Mac is online, for example that websites load in your browser. If Mail suddenly stopped sending and your internet is fine, the problem may be temporary at your email provider. Try again later.

2. Look for a status icon

A warning symbol or lightning bolt next to the account’s inbox in the sidebar means something’s wrong. Click it to see why.

  • Network offline, or can’t connect to the server: check for a VPN or other software that interacts with your network connection.
  • Login failed, or it keeps asking for your password: check with your email provider that the account is set up right and there’s no outage.

3. Check every address

Apple says some mail servers won’t send a message if even one address is wrong. Remove or fix bad addresses, then send again.

4. Try webmail

Sign in to your email on the provider’s website, like Gmail in your browser, and send from there. If that works, your account is fine and the problem is in Mail’s setup. Google gives the same advice for Gmail: if a message from Apple Mail is delayed, send it from mail.google.com or the Gmail app.

5. Check your storage and limits

Providers can limit how much mail they store, how many messages you send a day, and how big a message can be. To see how full your account is, Control-click the account’s mailbox in the sidebar and choose Get Account Info. Delete old mail (then choose Mailbox > Erase Deleted Items), or move it to a mailbox under On My Mac.

A big attachment can also be the problem. Gmail caps attachments at 25 MB. See File too large for Gmail? and Mail Drop not working?

6. Check for new terms

Providers sometimes pause email until you accept updated terms. Sign in on their website and look for a notice. For iCloud Mail, check System Settings for Apple Account or iCloud notices.

7. Check the outgoing server

  1. Choose Mail > Settings, click Accounts, and select the account.
  2. Click Server Settings, open the outgoing Account pop-up menu, and choose Edit SMTP Server List.
  3. Make the settings match what your provider says, then send yourself a test email.

On older versions of Mail, Apple also points to Window > Connection Doctor, and to checking that firewall software isn’t blocking ports 25, 465 or 587.

8. Remove the account and add it back

If nothing else works, Apple says to remove the account from Mail and add it again, choosing the right provider for your address.

Can’t see an attachment someone sent you? See Mac Mail attachments not showing. Sent one by mistake? See How to unsend an email on a Mac.

Sources: Apple Support If you can’t send or receive email on Mac, Apple Mail User Guide Send email messages and Verify an email account’s outgoing server, the macOS Sequoia Mail guide’s If you can’t send emails and Use Connection Doctor, and Gmail Help Send or unsend Gmail messages, checked October 27, 2026.

Or skip the mail app

Sendoff is a Mac app that lives in the notch and sends a file by Gmail or iMessage, without opening Mail. Drop the file, pick the person, press Send off. It remembers how you reach each person, like your accountant by Gmail and your mom by iMessage, and routes around what won’t work: a 48 MB video goes by iMessage instead of Gmail. You get 3 seconds to undo.

Sendoff isn’t out yet. Join the waitlist below, and tick the beta box if you want to test it first.