Can't join server when playing Oasis.

When the server is on Oasis I can't download the map for some reason. I can download all the other maps, but not this one in particular. Why is this? Where can I get the map?

Sounds like your map didn't download correctly, or got corrupt.

Browse to your steam folder and find steamapps/common/team fortress 2/tf/download/maps and delete any files named ph_oasis_a1.