Thank you Nick Cooper,
i also postet it there tomorrow! https://forums.gaya-simulations.com/topic/371-no-moving-sode-jetways-at-gate-1-5-at-the-berlin-tegel-airport-for-prepar3d-v45/?tab=comments#comment-1629
EDDT apparently only has some moving Sode jetways. For me, jetways only work at GATE 6, GATE 10 and GATE 13. For all others, I get an error message that there are no moving jetways available at this location!