Cannot start "Trouble with Darkspawn" quest

In Western Approach, after I rid the keep from the Venatori, Knight-Captain Rylen approaches you with couple of quests. One of them is the "Trouble with darkspawn".

Unfortunately, the first time he approached me I left conversation by mistake and didn't pick the option asking about the darkspawn. Now, even though he has a exclamation point over his head indicating quest, he doesn't offer any dialog options that lead to the darkspawn quest :-(

Since I cannot start the quest, does this mean I cannot find a way into the zone behind Door of Andoras?

Please help.

EDIT: issue fixed itself. I got the quest anyway, when I found the darkspawn in the "poison area" 

thx,

-Francisco