[Help] Stuck on "Hunting the Firehawk"

[Kowalski]

Hey guys, I was doing this mission and had to quit the game. When I started again I spawned at a chackpoint far from where I was before and needed to reach. But now, I can't find a way to reach the objective, I've walked all the map, but the only passage to where I need to go is unreacheble. Here's a screenshot of the map:
Map screenshot [i.imgur.com]
Basically, I need to go on the direction the marker is pointing, but it's a mountain and I can't climb it. Does anyone know what should I do?

[StephBx]

Go back north on the map and look for an tunnel openning with a bird metal sculpture in the front. your way is under the mountain.

[Kowalski]

Thanks for the help