From the walkthrough;
Quote
-To disable the anti-dragon zone around the mine, you'll need to find a
generator just west of the mine and flip a nearby lever in human form.

-Another lever can be found just southeast of Lord Lovis' tower.

-The next zone to disable requires you to land in the area only accessible
after flipping the prior lever (west of Lord Lovis' tower, just north of the
still active zone). Find and use a teleporter after you land, then locate and
flip the lever at the top of the new area to disable all but one remaining
anti-dragon zone.

-Next, disable the barrier by landing on a platform on the west side of Maxos'
temple and flipping the lever there. Geshniz's Headquarters can be accessed
via the teleporter on this platform.

-The last anti-dragon zone can be disabled by flipping a lever not too far
west of the zone itself (like the others, it's found inside of a thick-walled
fort easily visible on the map).

IIRC the last anti-dragon zone mentioned is the one around Rayhun's headquarters, with the generator north west of the village in the starting section, near where the necromancer's cave was (map).