Fix stuck email
Although email on webOS is usually a smooth and pleasant (albeit non-threaded) experience, it does tend to have some issues. The most notable is the pesky Yahoo Error 1299 that will cause your email to stop syncing, but there is another issue that also causes your email to stop syncing. You can press refresh and the dots circle around the number of emails and stops without any changes, with nothing new syncing in and even your email deletions not getting sent back to the server. Sometimes, you will also notice that some of your emails may sync, but the text of the email doesn't get downloaded. This appears to be caused by one specific email that must contain some special characters or some bad code that holds up the sync process. And while we tend to notice that this hits our Yahoo email most often, it has hit Google email as well.
In order to fix this, you need to find that one email on the server and delete it or move it to a different folder. You can try accessing the mobile mail site on your phone (for example, http://m.yahoo.com) or go to a desktop computer and access your mail from there. Try deleting a few emails at a time to find the culprit, or you can just do a mass move of the last handful of emails to another folder and check again to see if your email starts to sync again. I have found that email from the same sender has continued to cause this problem for me and I just unsubscribed from that email to "permanently" fix this issue.
It appears as if this issue (like the Yahoo 1299 problem) is no longer present in webOS 2.2 on the Pre3 or webOS 3.0 on the TouchPad, as email sync works on those devices, even though it will get held up on my Pre2. However, instead of stopping any sync from happening, that one problem email just does not get downloaded to either my Pre3 or TouchPad. So, if you have access to a Pre3 or TouchPad, one way to diagnose this problem is to compare emails between the server on the website vs the TouchPad and find the one email that does not match and delete or move it.