Jan. 25, 2015, 10:12 a.m.
Sure, here it is: https://steamcommunity.com/tradeoffer/new/?partner=212790765&token=vwXDtWQO
EDIT: I got it fixed after the 15 days steam guard period ended :)
This is what I could have guessed. :)
Oh, but in my opinion I guess that it should be able to accept the url even if the user can't trade, because when you try to use on-site purchase it'll require your url but it'll trade with your bot instead and not you ;) so it should require bot's url but not yours ;)