Every now and then, a pop up keep showing up and asking me to enter my gmail account password. Then sometime again, it pops up asking for the password again. What is this? And how do i stop it?
I had that too recently. Eventually, I had to delete the account and recreate it. Interestingly, doing so gave me back my folders, which had inexplicably disappeared. But I notice you can't actually access the folders, just move emails into them.
I had this with other email accouints as well. What I did once was getting frustrated and just hit cancel. It made the account invalid and I went back to that account and re-entered the password and its been fine ever since.
You should be able to see gmail folder contents -- at least, for contents which are not too old (determined by the "Messages Sync Timeframe" setting on the PB). For gmail folder contents, see p. 23 of the PB User Guide ("Refresh your Messages and Folders"), and this post:
This folder-related info is only for gmail accounts set up as Google Sync (=Exchange ActiveSync) accounts. (If you access gmail using POP or IMAP, the PB does not give access to folders.)
It seems that the email folder contents do not populate or synchronize automatically, you must manually ask for that for each folder. According to the manual, if there no email is shown, click on the "restart" icon (broken circle with an arrow); if some email is already listed, swipe down.