I postponed the mainquest. After completing and doing pretty much everything, i decided to resume. After "The Way of The Voice" i continued straight to "The Horn of Jurgen Windcaller", and then to "A Blade in the Dark".
At the beginning of the quest everything is fine, no bugs, no glitches. I kill the summoned dragon in Kynesgrove, absorb it's soul and get a message to talk to Delphine whos nearby. And here is a bug: there is no dialogue that proceeds to activate next quest.
I tried to use console commands to advance quest ( like setstage ... ), but it didnt help.
Also, during the Thieves guild quest to recover gems for the crown, i "accidentaly CHIMed" into the Embassy to get the gem. Now after that i was doing civil war questline for Empire, and had to use a console command that ended the whole Thalmor Embassy invitations, since Jarl Balgruf had that dialogue that allows to create a distraction during the reception. I have no idea if this might interfere with the MQ.
Anyways, thank you in advance for your help.
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"Wealth beyond measure, outlander."

...because if you are and advanced the MQ past Diplomatic Immunity that's most likely the problem. 

