Event managers get an error when the link for approving an event has expired.

[antontcymbal]

Event managers get an error when the link for approving an event has expired. Instead we should tell them that the event has expired and give them a simple way of requesting a new link, ideally in one click on the same page.

This is what they see at the moment:

[Ardnived]

On closer inspection. It's hard to determine what the real cause of this. Many expired sessions do show the correct warning message, rather than this error.

Perhaps there is a specific kind of email that consistently produces this error. If we can in the future we can track down the real cause of this error, that would be helpful.

I've updated the error page to something a bit more helpful though.