OS X Mail: Troubleshooting sending and receiving email messages

Learn how to troubleshoot Mail when it has issues sending or receiving email messages. Use this article to determine which part of the email "ecosystem" is the cause of the email issue, then attempt to resolve it.

Here are the four parts of the email process that make up the email "ecosystem":

  1. The email message has to be addressed properly, with content that is allowed by the email service provider for both sender and receiver.
  2. Mail needs the correct email account settings for the email service provider.
  3. An Internet service provider that allows Mail to communicate to the incoming and outgoing email servers of the email service provider.
  4. The email service provider's email servers must be up and running. Also, the email account must not be suspended and must accept the email account password sent from Mail.

Note: Your Internet service provider, such as Comcast, RoadRunner, AOL, and so forth, may not be the same as your email service provider, such as Gmail, Hotmail, Yahoo!, Apple's MobileMe, or others.

First confirm these three things with your email service provider (ESP)

Contact your ESP's support staff (or visit the ESP's support website), then confirm the following:

  1. The ESP's email servers are up and running.
  2. The email account password you are using is correct, and it is being accepted.
  3. That your email account is capable of sending and receiving email messages; it has not been deactivated.

Note: The above items are not unique to Mac users. If your email service provider refers you to AppleCare because you are using a Mac, please request again that they first check the above items. Issues with the above items cannot be resolved by Apple.

If your email service provider confirms that the above three items are OK, you can use this article to troubleshoot the Mail issue. 

Tip: If you see a sheet or dialog that states 'Enter the password for user "email address'", this indicates that the email service provider is having an issue with the password being sent by Mail, or there is an issue with the email account. Contact the email service provider for support. Choose Window > Connection Doctor click "Show Detail" then click "Check Again". The information displayed in the "Show Detail" drawer may include details from the email service provider about what the issue is. Look for headers that start with "[ALERT]".

Open Mail Connection Doctor

In Mail, choose Window > Connection Doctor.

Tip: If you see a spinning gear in Mail or the Mail Connection Doctor, choose Window > Activity to learn what Mail is doing.

Collapse All Sections | Expand All Sections (Or, click to a specific topic below that lists your issue.)

The Connection Status at the top of the Mail Connection Doctor window shows a red dot (little red dot) and "Mail was unable to connect to the Internet."

Click "Network Diagnostics…" for help diagnosing the Internet connection issue. After you have resolved the Internet connection issue, continue with this article if the Mail issue persists.

Mail Connection Doctor shows all green dots (little green dot) in the Status column

Mac OS X v10.6.8 only: Click here if the Send button is dimmed, and or the Outgoing Mail Server (SMTP) is set to "None"

  1. In Mail Connection Doctor, double-click the affected Incoming email account (such as IMAP or POP). This will open the preference settings for your affected account. In the above screenshot, this would be the "MobileMe" account.
  2. Make sure you have chosen the correct "Outgoing Mail Server (SMTP)" from the pop-up list. In the below example, it would be "smtp.me.com:meichen3".
  3. Close Mail Preferences, then click Save.

Make sure the email message addressed properly and the "To" & "Cc" fields are correct

To display the actual email address, you may have to click the down arrow that appears to the right of the recipient's name when your mouse pointer is over it.

  1. If the recipient is in your Address Book, open Address Book, then edit the card for this contact. Enter the correct email address.
  2. If the recipient is not in your Address Book, but you have emailed them previously, the address you used will be in the "Previous Recipients List" (and autofilled when you type in their name).

    Tip: Even if the previously-used email address is not correct, AutoFill may continue to use it. To clear an email address from the "Previous Recipients List", click the down arrow that appears to the right of the email nickname when your cursor is over it and from the contextual menu select "Remove from Previous Recipients List".

    Note: If you do not see "Remove from Previous Recipients List" in the contextual menu, then the email address is in your Address Book and you should follow step 1 above.
  3. sample message with Remove from Previous Recipients List selected

Click here if you are attaching a large file

Message attachments cannot be larger than what is allowed by the recipient's and your email service provider(s). The exact limit may vary by email service provider. Please check with the recipient's and your email service provider for details.  Try sending your email message without an attachment to see if that works.

Click here if you have an email message signature with graphics or URLs in it

Signatures can include graphics as well as URLs. Not all email servers handle these graphics and URLs as expected. The recipient's email service provider, or your email service provider, could have an issue with your signature. Try sending the message without the signature, or with a text-only signature.

Make sure you have not exceeded your email provider's account quota

  1. In Mail, click the Inbox of your account.
  2. Press Command-I to open your "Account Info" window.
  3. After Mail completes a scan of your email account, click the "Quota Limits" tab, as shown in the example below.
  4. Depending on your service provider, you may see how much space your account is using and how much space is available to you. If you are at your quota limit, delete messages from your email server until you are under the quota limit.

    Note: Some email service providers may not work with the Account Info function.

Account Info with Quota Limits tab selected

Note: It may take your email service provider 24 hours to clear the quota limit.

If the email issue persists, rebuild your affected mailbox

Some email issues can be caused by an improperly cached mailbox or individual problematic email message.

To rebuild a mailbox, follow these steps:

  1. Select your Inbox mailbox, or Command-click multiple mailboxes.
  2. Choose Mailbox > Rebuild.

Tip: Choose Window > Activity to view the progress of the mailbox rebuild.

Activity example

If the mailbox rebuild stalls

A problematic email message may cause Mail to stop rebuilding your mailbox. You can verify this by reviewing the Activity window to discover where the progress bar stops when caching your messages. In the above example, the rebuild stalled at email message 4934 of 7023 (the first line of activity).

To purge the problematic email, follow these steps:

  1. Click the stop sign in Activity monitor until it stops all processes.
  2. In Mail choose View > Columns > Numbers.
  3. Select a deletable message that has a number less than the problematic email message.
  4. Command-click the problematic message (hold the Command key when you click).
  5. Choose Delete.
  6. Repeat the mailbox rebuild until it completes.

If the email issue persists, continue with this article.

Mail Connection Doctor shows one or more red dots (little red dot) in the account Status column

Check your Incoming IMAP or POP and Outgoing SMTP email account settings

Use Apple's online Mail Setup Assistant to discover what the correct settings should be for both your Incoming (IMAP or POP) and Outgoing SMTP email servers. If your email service provider is not listed in the Mail Setup Assistant, visit your email service provider's website or contact their support staff to get the correct settings. You can use this "cheat sheet" when asking your email service provider about the settings you need.

After you have the correct email service provider settings, make sure Mail is configured properly.

Click here if your Incoming and Outgoing email account settings are correct, but the issue persists

What alert message is shown in the Mail Connection Doctor "Details" column affected account?

Click here if a "Could not connect to this (server type) server…" message appears

Check for third-party firewall software

Third-party firewall software, such as Little Snitch or Symantec Norton Personal Firewall, could be blocking the necessary ports. If such software is installed, make sure the firewall is not blocking these ports:

  • ports 25, 465, and 587 (for sending email via SMTP)
  • ports 143 and 993 (if you use IMAP email)
  • ports 110 and 995 (if you use POP email)

If you're not sure how to enable the correct ports, try disabling the third-party firewall completely, then test for the Mail issue. Note: The Mac OS X v10.6 firewall does not interfere with ports needed to send email.

Check for Internet Service Provider port blocking

Your Internet Service Provider may be blocking the SMTP ports needed to send email.

You can use Apple's MobileMe service to find out if your Internet Service Provider is blocking the sending email protocol SMTP:

  1. Open Network Utility.
  2. Click the "Port Scan" tab.
  3. Enter "smtp.me.com" in the "Enter an Internet or IP address to scan for open ports" field.
  4. Enable "Only test ports between _ and _", and enter 25 for both port fields.
  5. Click "Scan" to test.

If you do not see "Open TCP Port: 25 smtp", contact your Internet Service Provider or visit their support website for further assistance. If you do see "Open TCP Port: 25 smtp", your Internet Service Provider is not blocking the SMTP ports needed to send email. Go to the "'Trying to log in to this (email server provider name) account failed…' message or any other error message appears" section below if the email issue persists.

Click here if a "Trying to log in to this (email server provider name) account failed…" message or any other error message appears

Are you connected to the Internet from a different location or via a different ISP than you usually use (such as a new Wi-Fi hotspot)?

Yes, I am connected from a new location

  1. In the Mail Connection Doctor, double-click the row that has a red dot next to an account name containing "smtp".
  2. Click the Advanced tab.

If your Internet service provider and email service provider are the same company, and your SMTP authentication is set to "None", you may be able to send email only when you are directly connected to the Internet via your Internet Service Provider.

If you are connected to the Internet through other means, such as a Wi-Fi hotspot, you may not be able to send email through this server (but you may be able to receive email and surf the web). Contact your email service provider to see if they have an "off network" SMTP server setting that you can add to your account for such situations, or use a different SMTP server that you have configured, such as MobileMe if you use it. MobileMe offers a free trial.

You can use this email "cheat sheet" to make sure you ask the email service provider all of the relevant questions about the configuration.

No, I am not connected from a new location

A small alert icon next to your inbox

If a small alert icon appears next to your Inbox (Alert icon or ), click the icon.

  • If "Enter Password for Account…" appears, this indicates that your password is incorrect. If you cannot recall what the password is for your email account, contact your email service provider for support or visit the ESP's support website for a password reset tool (see below).
  • If "The server returned the error:…" appears directly above the "Stay Offline" button, there is an issue with your email account. Make note of what the alert message is (following "The server returned the error"). The message should give you an indication of what the issue is, or may contain a link that you can copy and paste into your web browser to find help for the issue.

    In the below screenshot, the Gmail servers have an issue with an account. If you copy and paste the link "http://mail.google.com/support/bin/answer.py?answer=78754" from the alert, it will take you directly to the support page that can help you with this issue. Contact your email service provider for support.

    Unable to connect alert message

Try webmail

Many email service providers offer a webmail interface that you can use to access your email via a web browser, such as Safari. If your email service provider has a web interface, open Safari, go to the webmail website, and log in with your user name and password. If your user name and password are not accepted, you may need to reactivate or reset them.

Note: The webmail interface is via your email service provider's web server, which is different than an email server. If there is an issue with your email service provider's email server, but not their web server, you may have issues in Mail but not in the web interface to your email. Contact your email service provider support staff to check on the status of the servers.

Reset your email account or password

Here are some email service provider web tools for reactivating an email account or resetting a password:

Make sure you update your settings in Mail if you change your password.

You should not alter the contents of the "~Library/Mail" folder

Important: Unless directed by an AppleCare Advisor, you should not use the Finder to alter the contents of your "~/Library/Mail" folder or its subfolders. Doing so circumvents Mail's ability to keep track of email messages, mailboxes, attachments, and so forth, and may result in data loss or other Mail issues.


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