An important e-mail I sent to a client went into my Drafts Folder instead of being sent.  I didn't find this until I came across it by chance a few days later.  I then clicked on "continue", amended the e-mail and resent it - and assumed that it had gone.  The following day I checked the Drafts Folder and it was still there!  I then telephoned the client as is it was safer!  

The same thing has happened to a friend of mine, who responded to an e-mail which I had sent him, but I didn't receive it.  When he checked, it was also in his Drafts Folder.  What is going on?  Please can you help?