I am having trouble with one of my accounts in the Android mail app. Whenever I try to send an email I get a notification saying "syncing mail" then a notification "failed to send mail". The message doesn't show in the outbox, if I tap the notification it loads the compose message page, with my message loaded.

I am able to download and read messages from that account and I am able to send mail via the account from a web browser, and I am able to send messages from the app using a different account. I have tried logging out of the app and back in but that hasn't helped.

Any ideas how to solve this?