If you (and your entire fireteam if you're in a fireteam) go to orbit, then come back to the Dreaming City does it work or are you completely unable to activate it at any time in any instance of the Dreaming City? There is a known glitch that if two or more players try and submit a token to the BW at the same time that the Well locks up. Once that happens the Well in that loaded instance will be permanently unusable. You fix it by leaving the instance. If you're by yourself the easiest way to do this is to re-load yourself onto the Dreaming City map. If you're in a fireteam then the fireteam leader needs to take your team to orbit, then back down to the planet.