Emails stuck in outbox

[RogB]

Most emails are sent OK but some stay in outbox with Network Failure indicated. If I hit Edit button I then have Send option and away it goes. Ruled out FIOS router as my wife's S5 never does this. Happens with other routers as well.

 

[Rukbat]

That's a problem on the email server end. It could be your account that's a bit flaky, or you may be using a different SMTP server than your wife is.