it's possible she doesn't meet the prerequisites for the next mission
the mission after clues of the resistance is outpost of the resistance...
if outpost of the resistance is the mission your friend completed, the next one would be
spy on the resistanceSpy on the Resistance requires 75 cloak
Ask your friend to look for "Spy on the Resistance" in the mission list to see if its button is gray, and if so that is what the problem is.