How to Fire SOS During expedition

[I'M NUCLEARRRRRRRR]

I am connected to the servers and am online however it simply will not let me fire it off during an expedition, how do I do this?

[DaTank]

Is the expedition for a quest? If so you still have to watch the cut scene.

[Reborn]

are you doing a mission that has you do an expedition? then there might be a cutscene you need to watch before you're open for SoS

[SictionArc]

when a cutscene for a quest battle ends you will be able to fire a sos flare i cannot say the same for non quest battles