Hi, I'm playing a nord character and on level 14, using PC version of legendary edition.

I'm at the point where I've met Melborn at the embassy bar and I'm dressed in party gear. The quest is telling me to create a distraction and slip away, the pointer is on Melborn and when I talk to him, only 2 answers come up about having a drink and when I click on the other dialogue option he just says he's run out of that bottle of wine or something (I'm typing this on a different PC so can't remember exactly what the other line was) and he's now standing next to a door behind the bar, but nothing happens and I can't open the door.

What can I do to continue in this quest? thanks in advance.