Apple Mail Not Sending Emails on Mac? How to Fix It

Short answer: When Mail on a Mac won't send, the problem is almost always the outgoing (SMTP) server: a password Mail no longer has, a missing or wrong server in the account's settings, a network that blocks sending, or a provider limit you've hit. Click the warning icon next to the account first, since it usually names the cause. Then check the outgoing server under Mail > Settings > Accounts > Server Settings, re-enter your password in System Settings > Internet Accounts, and if nothing helps, remove the account and add it back with the right provider option.

The steps below are for macOS 27 and also work on macOS Tahoe 26, Sequoia 15 and Sonoma 14. Start at the top: the quick checks solve most cases in a couple of minutes.

Quick checks (2 minutes)

Look for a status icon. A warning symbol or lightning bolt next to the account's inbox in the sidebar (or at the top right of the Mail window) means Mail has a problem with that account. Click it: the message usually says whether the login failed, the server can't be reached or the account is offline.
Check your internet and any VPN. If websites load but Mail says it's offline or can't reach the server, Apple's advice is to look for a VPN, firewall app or other software that filters network traffic, and turn it off to test.
Try sending from webmail. Sign in to your provider's website (iCloud.com, Gmail, Outlook.com) and send a message there. If webmail can't send either, the problem is the account or the provider, not Mail.
Check the provider's status page. Apple System Status covers iCloud Mail; Google and Microsoft have their own (links in the sources below). Short outages don't always show up there.
Quit and reopen Mail. Then choose Mailbox > Online Status and make sure every account is online. If Mail won't open again, see Mac Mail not opening or freezing.

Mail receives but won't send

This is the most common version of the problem, and it narrows things down a lot. If new mail arrives, your account, password for incoming mail and internet connection are fine. Sending uses a separate outgoing (SMTP) server with its own settings, so look there:

The outgoing server is missing or set to None. In Server Settings, the Outgoing Mail Server (SMTP) "Account" pop-up should name a server, not None. Fix it in the next section.
The outgoing password is out of date. If you changed your password recently, Mail may have updated it for incoming mail but not for sending. Re-enter it in the outgoing section or in Internet Accounts.
The network blocks sending. Some office, hotel and public networks block the ports used to send mail. Try another network, such as your phone's hotspot. If it sends there, ask the network's owner or use the port your provider lists (often 587).
You've hit a sending limit. Providers cap how much you can send per day (see below). Mail keeps the message in the Outbox until the limit resets.

Messages sitting in the Outbox are a symptom of all four. If that's what you see, our guide to messages stuck in the Outbox covers how to send, edit or delete them.

Check the outgoing (SMTP) server settings

In Mail, choose Mail > Settings, click Accounts, select the account, then click Server Settings.
Under Outgoing Mail Server (SMTP), check that the Account pop-up shows a server, and that User Name and Password are filled in. Retype the password if you're not sure it's current.
Leave Automatically manage connection settings turned on unless your provider gives you specific settings. If you turn it off, enter the Port, turn on Use TLS/SSL and choose the Authentication method your provider lists.
Click Save, then send yourself a test message.

Common outgoing settings from providers' own help pages:

Provider	Outgoing server	Port and security	Note
iCloud Mail	smtp.mail.me.com	587, SSL (or TLS/STARTTLS)	Use your Apple Account email and password
Outlook.com, Hotmail	smtp-mail.outlook.com	587, STARTTLS	Needs Microsoft sign-in (modern authentication); a password alone fails
Gmail	Set automatically	Set automatically	Add the account with the Google option and let Mail manage the settings
Other providers	From your provider	Usually 587 (STARTTLS) or 465 (SSL/TLS)	Check your provider's help page

How to set up or change the outgoing mail server

If the outgoing server is missing, or you need to add one your provider gave you, use the SMTP server list:

Choose Mail > Settings > Accounts, select the account and click Server Settings.
Click the outgoing Account pop-up menu and choose Edit SMTP Server List.
Click the Add button (+), then enter a Description, the server's Host Name, your User Name and Password. Set the port and security, or leave Automatically manage connection settings on.
Click OK, choose the new server in the Account pop-up, then click Save.

In the same list you can remove old servers you no longer use, which avoids Mail picking the wrong one. The Advanced section has an Allow insecure authentication option: only turn it on if your provider tells you to.

Fix password and sign-in problems

If the status icon says the login failed, or Mail keeps asking for your password, quit Mail and open Apple menu > System Settings > Internet Accounts. Click the account, click Details if you see it, and type your current password.

For Gmail and Outlook.com accounts, a password alone often isn't enough anymore. Google no longer accepts username and password sign-in from older apps for Google Workspace accounts, and Microsoft ended basic authentication for Outlook.com in September 2024. The fix is to remove the account and add it back with the right option, so you sign in on the provider's own page: Google for Gmail, and Microsoft Exchange for Outlook.com, Hotmail and Live addresses on a Mac. Our guide to the "Unable to verify account name or password" error goes through each provider.

Check sending limits and message size

Provider	Daily limit	Size limit
Gmail	500 emails a day, or one message to more than 500 recipients	25 MB (bigger files go as Google Drive links in Gmail itself)
iCloud Mail	1,000 messages and 1,000 recipients a day; 500 recipients per message	20 MB, or up to 5 GB with Mail Drop

If you hit a limit, wait for it to reset (about a day) and send again. For a big attachment, let Mail offer Mail Drop when it asks, or share the file with a link. On iCloud, a sending problem can show up as "Cannot send message using the server iCloud."

Still not sending? Deeper fixes

Use Connection Doctor

Mail still has a diagnostic tool under Window > Connection Doctor in macOS 27, even though Apple stopped documenting it after macOS Ventura. It tests each account's incoming and outgoing servers and shows which one fails. Click Show Detail to see the server's replies. Our guide to Mac Mail not connecting to the server explains its error messages, including "Connections to host (null) on the default ports failed".

Check for new terms or a blocked account

Apple notes that providers sometimes need you to accept new terms and conditions before mail works again. Sign in to webmail and look for a notice. A provider can also suspend sending if it thinks the account was hacked; webmail will tell you if that happened.

Remove the account and add it back

This is Apple's last step, and it resets every setting. For IMAP, iCloud, Gmail and Exchange accounts your mail stays on the server, so nothing is lost; Mail downloads it again. In Mail, choose Mail > Accounts (this opens Internet Accounts), select the account and remove it. Then add it again, choosing your provider from the list rather than "Other" where possible. If you use POP, back up your local mailboxes first, because POP mail lives only on your Mac.

One setting worth knowing: in Mail > Settings > General, Automatically try sending later if outgoing server is unavailable keeps unsent messages in the Outbox and retries them, so a brief outage fixes itself.

If Mail keeps letting you down

Disclosure: we make Canary Mail. If sending breaks again and again across several accounts, it can be worth trying another app. Canary Mail is an email app for Mac, iPhone, iPad, Windows and Android that works with Gmail, Outlook, iCloud, Yahoo, Exchange and other IMAP accounts. The free plan covers unlimited accounts on 2 devices with AI inbox sorting; the Growth plan ($36 a year) adds AI writing and summaries, read receipts and send later. More than 2 million people use it, and Apple has featured it on the App Store and the Mac App Store.

Be clear about what switching can't fix, though: if your provider is down, your password is wrong or your mailbox is full, every email app will hit the same wall.

Frequently asked questions

Why are my emails not sending on Mac Mail?

Usually because of the outgoing (SMTP) server: an outdated password, a missing server in Server Settings, a network that blocks sending or a daily sending limit. Click the warning icon next to the account to see Mail's reason, then check Mail > Settings > Accounts > Server Settings.

Why does my Mac receive emails but not send them?

Receiving and sending use different servers. If mail comes in, the account works, so check the outgoing server: make sure it isn't set to None, retype its password, and try another network in case yours blocks sending.

How do I fix the outgoing mail server on a Mac?

Choose Mail > Settings > Accounts, select the account and click Server Settings. Check the Outgoing Mail Server (SMTP) section, or choose Edit SMTP Server List from its Account pop-up to add or correct a server. Click Save and send a test.

Why are my emails going to the Outbox and not sending?

Mail moves a message to the Outbox when it can't reach or sign in to the outgoing server, and retries later. Fix the server or password problem and it sends. Our Outbox guide covers stuck messages.

Is there a current problem with Apple Mail?

Check Apple's System Status page for iCloud Mail, or your provider's status page for Gmail or Outlook. If webmail works but Mail doesn't, the problem is on your Mac, not a wider outage.

How do I reset Mail on my Mac?

There's no reset button. The closest thing is removing the account in Internet Accounts and adding it back, which resets its settings. Mail on IMAP, iCloud, Gmail and Exchange stays on the server and downloads again.

Other Mac Mail fixes

Sources

Try another email app for Mac

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