WHen Harkon turns to a vampire lord to demonstrate his power to convince me, I get CUT OUT OF THE DIALOGUE and he banishes me!

I want to side with the vampires but after 5+ times loading the same happens every time. I dont get the conversation option to become one of them. The last option I can click is "Im allready a vampire, what more can you offer?" then he transforms and banishes me without any option to accept or decline.

Any workaround with console? (Playing on PC)

Nevermind sorted it out

perhaps you should write how you fixed issues in case others suffer from it