Are you using tf_bot_add?
If so, you have to use a popfile that works with your map. Try finding the default popfile for coaltown on mvm.tf and use that as a baseline. Also, make sure your spawns are named correctly. Robots are programmed to spawn at a spawnpoint with a particular name (this is specified in the popfile). Make sure your spawnpoints for blue are named accordingly, or else they either wont spawn at all, or spawn somewhere totally random (in this case, in red spawn).
Hope this helped