This explains why sometimes email can be slow when using the “Gmail to check and send email using your server (EG email@example.com)” method.
How it works.
With this particular type of configuration, Google’s servers log into your server and downloads the messages to their servers. Unfortunately the amount of time that it takes for fetch messages via POP3 is entirely up to Google – it’s their servers that make the outbound connection and downloads the messages. Unfortunately, there’s no way to change the default time that Gmail will wait between connections.
That being said, I’m quite familiar with this type of setup as I use it on a personal email address of mine, and do know that the delay varies quite a bit, but it’s possible to force Google to fetch messages via POP3 by clicking the “Refresh” button in the Gmail interface.
This should force Google to make a connection to your server and fetch messages. There may even be a delay after performing this though, so you may have to wait a few minutes and hit refresh again in order to actually view the fetched messages. I know this isn’t as convenient as just having it constantly check messages, but again, there’s no way to configure Gmail to check things at quicker intervals.
If you still encounter issues after performing this, you can navigate into the Gmail settings page and click on “Accounts and Import’ – then under the “Check mail from other accounts” you should see your POP3 account setup. You can click on “Check mail now”, which forces a check to occur and if Gmail has issues connecting, you should see an error on the page. It’s also possible to click on “View history” and it’ll show you recent outbound connections and let you know if it’s downloaded any messages and at what times connections were made.