When you have this problem, you need to pick a different mission, if you try to get a clearance from ATC, the mission is all messed up.
Usually I can request IFR Clearance. Once you get takeoff clearance, you cancel IFR and go on with the mission.
For landing, there is the option to ignore weather conditions and then you can continue with the landing procedure normally.
So far this workaround worked for me, but I haven’t experienced the issue more than two times.
Had this also
But ONLY on days the weather in real life was IFR also that airport
So i think that despite clear skies visually … i is checking real world data and denies the VFR
When the same airport was VFR in RL … it also was in the sim.