Mail stuck on sending
I sent 2 emails with attachments 5 hours ago which took a while for them to send (don't normally have a problem). They have since been sent but my email is stuck on 'sending 12 of 12 messages' .... but I'm not sending anything and there's nothing in the Outbox. I've closed the programme and reopened it and its still there, and I've now deleted that account and its still there. It now says 'sending 14 of 14 messages' ?????
I can't send anything else either.
MacBook Pro (17-inch Early 2011), OS X El Capitan (10.11.5)