I got a complain from email user that they did not receive email from some of their contact. I guessed it must be caused by spam filter in the mail server. I hosted company’s email at ISP. ISP’s webmail also did not have a Bulk folder, so email suspected as spam will be permanently deleted. Therefore I move all emails to GMail and use their Google Application service.
The problem came when I need to access email from several mail clients. They did not receive all messages, only a part of it. The solution can be achieved from help center. For a short, you just need to set POP username from: firstname.lastname@example.org to recent:email@example.com and set leave all messages in the server. “Recent:” prefix is to fetches the last 30 days of mail, regardless of whether it’s been sent to another POP client already.