Hi, I recently stopped using the Pre2 due to mystery battery drain issues. However, the Pre3 stopped syncing to Yahoo 2 days ago. Both are on 2.2.4
I fired up the Pre2 and it works fine with Yahoo (once I put in my post-heartbleed password update), but didn't like Google (unknown error). I couldn't find any problem with the Pre3 settings and it never reported an error. Often when I have an error, I check the settings and see too few dots in the password field an assume the machine has 'forgotten' the password. Usually, re-entering solves the problem, BUT actually I often see what appears to be a truncated password and the sync still works fine..?
Anyway, ultimately the problem was solved by removing and re-adding the yahoo acount. I guess some glitch can develop somewhere that's not user re-setable and you just have to start from scratch.
Back on the Pre2 I did all kinds of stuff to re-enable the google account, but no joy, so I removed and re-enabled it and it was STILL not working! It was only on the verge of giving up that I remembered the google https patch I had to recently add to the Pre3. Off to add it to the Pre2 now...
There has been talk of 'updating the update guides' for a while and lacking an official or unofficial update mechanism, a comprehensive guide that at least lists all the hoops we now need to jump through seems necessary and I will look into it.
Anyhow, my best advice is: try removing and re-adding the account - the default yahoo template should work or the settings from the 1299 error link if you add it manually. I use imap, not pop.
If you can upgrade to 2.2.4,.. I guess it's up to you.