You've just dashed off a reply to an important email message. When you hit the 'Send' button, you discover that it's dimmed, which means you can't send your message. Mail was working fine yesterday; what went wrong?
A dimmed 'Send' button in Apple Mail means there isn't a correctly configured outgoing mail server (SMTP) associated with the Mail account. This can happen for a number of reasons but the two mostly likely are that the mail service you use made changes to its settings and you need to update your settings, or your Mail preference file is outdated, corrupt, or has the wrong file permissions associated with it.
Outgoing Mail Settings
Occasionally, your mail service may make changes to its mail servers, including the server that receives your outgoing email. These types of mail servers are frequent targets of malware designed to turn them into zombie spam servers. Because of the ever-present dangers, mail services will occasionally upgrade their server software, which may in turn require you to change the outgoing mail server settings in your email client, in this case, Mail.
Before you make any changes be sure that you have a copy of the settings required by your mail service. In most cases, your mail service will have detailed instructions for various email clients, including Apple Mail. When these instructions are available, be sure to follow them. If your mail service only provides general instructions, this overview on configuring your outgoing mail server settings may be helpful.
Configuring Your Outgoing Mail Settings
- Launch Apple Mail and select Preferences from the Mail menu.
- In the Mail preferences window that opens, click the 'Accounts' button.
- Select the mail account you're having problems with from the list.
- Click the 'Account Information' tab.
- In the 'Outgoing Mail Server (SMTP)' section, select 'Edit SMTP Server List' from the dropdown menu.
- A list of all the SMTP servers that have been set up for your various Mail accounts will display. The Mail account you selected above will be highlighted in the list.
- Click the 'Advanced' tab.
Here you can configure the SMTP server settings to match those provided by your mail service. If your mail service uses a port other than 25, 465, or 587, click the 'Custom port' radio button, and add the port number provided by your mail service. Otherwise, leave the radio button set to 'Use default ports.'
If your mail service has set up its server to use SSL, place a check mark next to 'Use Secure Sockets Layer (SSL).'
Use the Authentication dropdown menu to select the authentication type your mail service uses.
Finally, enter your user name and password. The user name is often just your email address.
Try sending the email again. The 'Send' button should now be highlighted.
Apple Mail Preference File
The other possible culprit is your Mail preference file, which stores the configuration information for each of your Mail accounts. If the Mail preference file becomes corrupt, or unreadable because of permission issues, it may cause Mail to stop working, or prevent certain features, such as sending mail, from working correctly.
The Apple Mail preference file is located at: /Users/user_name/Library/Preferences. For example, if your Mac's user name is Tom, the path would be /Users/Tom/Library/Preferences. The preference file is named com.apple.mail.plist.
One possible cause of a problem is a permission issue, which will prevent Apple Mail from writing data to its preference file. This type of permission problem will prevent you from saving updates to your Mail settings. How does this happen? Typically, your mail service tells you to make changes to the settings for your account. Your make the changes and all is well, until you quit Mail. The next time you launch Mail, the settings are back to the way they were before you made the changes.
To correct file permission issues, follow the steps outlined in the 'Using Disk Utility to Repair Hard Drives and Disk Permissions' guide.
Once you're finished with the above guide, try Mail again. You may need to re-enter any recent changes to the Mail settings, per your mail service. But this time you should be able to quit Mail and retain the settings.
If you still have problems with Mail and sending messages, take a look at the Troubleshooting 'Apple Mail - Using Apple Mail's Troubleshooting Tools' guide.