I have an Android phone (Galaxy S3, v4.4.2) and have configured mail to use my Microsoft Exchange account. Everything was working fine for many months until one day I composed a new email, but lost my network connection while I was trying to send it. I got an error message that it failed. Now every time I power the phone on (which is every morning), I get a notification that sending that email has failed. The email does not show up in the Drafts folder or Outbox, which are both empty.
How do I clear out this error?