This is a server/game related issue I believe and it will not fix itself until the server had a restart.
Had quite a few users mentioning this now over the last week and I'm afraid it will not get sorted until we had one of these restarts. This from what I can understand happens because the map process itself starts and stops, starts and stops, starts and stops, starts and stops, because users run in and out of the map a lot, but it doesn't remain at least 1 user at all times keeping it running. The more a map starts and stop as soon as there's no users online in it, it's more likely to get stuck at some point when trying to start.
All you can do is to hang in there and try at a later time when a restart has taken place.