Configuring POP or IMAP access for your email account is very similar to configuring POP or IMAP access in Gmail. In addition to the Gmail Help Center, here's what you need to know:
Enable POP or IMAP in your Google Apps email account:
1. Click Settings at the top of any page.
2. Click the Forwarding and POP/IMAP tab.
3. Enable POP or IMAP.
4. Click Save Changes.
Any time you're asked for your username during the configuration process in your client, you'll need to enter your full email address (username@your_domain.com).
For POP access, refer to the Gmail POP instructions for the incoming and outgoing servers.
For IMAP access, refer to the Gmail IMAP instructions for the incoming and outgoing servers.
If this didn't help, please visit the Gmail Help Center for POP troubleshooting and IMAP troubleshooting.
If you're receiving repeated prompts for your password, ensure that your Google Apps password has at least 8 characters and clear a captcha for your email account.
How to clear a captcha
Disable all POP clients you're using to read mail. If you use one at work and one at home, please disable both.
From the computer on which your POP logins are failing, visit https://www.google.com/a/your_domain.com/UnlockCaptcha. Be sure to replace 'your_domain.com' with your domain name.
Enter your email username and password, and the letters in the distorted picture.
Once you have successfully signed in, restart your mail client and try to download your mail.
To verify that the necessary ports for POP access aren't blocked, please perform the following test on your computer:
How to check port access
Open the Start menu, and select Run.
Enter command in the 'Open:' field, and click OK.
Enter telnet pop.gmail.com 995 in the new prompt window, and hit Enter.
Repeat steps for telnet smtp.gmail.com 465.
If the information in the prompt windows clear, the ports are not blocked. If you receive an error message, the problem you've experienced is a result of your network servers and/or security firewall. We recommend contacting your local network administrator or Internet Service Provider (ISP) for more information.