For me, whether I use googlemail.com or gmail.com as the server, the following error occurs consistently, and has also been well documented on many forums and discussions boards throughout the internet:
When I connect to my gmail inbox by pop3, it downloads my mail fine. Then after I *disconnect*, and reconnect to retrieve mail the next time, the previously downloaded messages disappear completely from my phone's inbox and I get the message "No new email messages."
Even previously downloaded messages which were there a minute ago, vanish from the phone's inbox completely. As long as you stay connected you can retrieve as many times as you wish, but once you disconnect and reconnect again, all messages vanish.
This happens regardless of what pop3 settings you choose at gmail's configuration page. All messages, messages since whenever date, etc, etc.. I've tried every option and nothing makes a difference.
It has nothing to do with messages being deleted on the gmail inbox. They are still there if I log in from the web, but do not show up on my phone. Once you download them once, then disconnect, then reconnect, and try to download again, all messages vanish. If a new message arrives you will be able to download it, but again only the first time. The next time you try to retrieve, that message will be eliminated from the inbox.
"Leave message on server" is selected and it still doesn't make any difference. It seems that once a message is flagged as "already downloaded", it will vanish the next time you try to check mail.
There are workarounds: choosing to only download the first 999K of any message as your default, instead of "whole message and attachments" will leave the message flagged as "not completely downloaded" on gmail's system, and it will not vanish then ext time you check it. However this type of option isn't available from many desktop email clients, so if you want to be able to access your mail from both phone and PC, it won't work. Once you download mail from your computer (again, even selecting to "leave messages on server") you will no longer be able to get the messages on your phone, as they will now be considered "already completely downloaded" and get wiped fro myour phone's inbox.
You can also choose to use "recent:
[email protected]" as your login name, which will avoid the message-wiping problem. But that will only keep messages from the last 30 days. If you want months or years worth of emails to remain accessible in your phone's inbox, that solution won't work.
Don't ask me how a problem at Gmail's server is actually causing my E61 to erase messages from the inbox. Previously downloaded mail should always remain in the inbox, regardless of whether anything *new* is found while checking the server. Even if everything were to be deleted off the server, the stuff you downloaded should still remain there, just like it does on any desktop email program like Thunderbird. On Thunderbird, downloaded messages do stay in the inbox, but if you access them with your phone first, Thunderbird will fail to retrieve them when you check. Even if you select to download "all" messages and not just new ones, somehow that "already previously downloaded" flag kicks in and prevents Thunderbird from getting them.
Gmail seems to be treating its pop3/smtp accounts as some sort of IMAP hybrid, where the content is always synched between all devices. Somehow that signal must be getting accepted by my phone, and when it is told that there are "no" messages on the gmail server, it responds by making sure that NO messages show up on my local E61 inbox.
But that's not how POP3 is supposed to work. What gets downloaded to Vegas is supposed to STAY in Vegas, not disappear the next time a download is attempted.