Hey there,

I have two machines running Lion with latest updates and the latest
Mailplane preview. For a few days, I was unable to send anything from one
of them, save drafts, or attach files, and the "Chat" on the side was
almost constantly unavailable.  The machines are setup very similarly with
virtually identical options in Mailplane.  GMail in the Chrome web browser
worked fine during this time.  

I tried checking for updates to Mailplane, restarting Mailplane, restarting
the computer, checking for updates in the OS, and turning on/off the system
webkit and flash, all to no avail.  I tried multiple different network
connections as well (work and home WiFi).  

I was finally able to resolve the problem when I switched from "rich text"
composer to plain text composer and everything started working again.  I
was able to switch back to rich text and things continued to work.

Just thought I'd mention this as the problem and the apparent resolution
were so weird.  

The error I was seeing constantly on send or save looked like this:

http://dl.dropbox.com/u/3186140/Screenshots/Mailplane%20failure%20on%...