His conversations w/Kislyak were not a crime. They were his job.
"The FBI in late December reviewed intercepts of communications between the Russian ambassador to the United States and retired Lt. Gen. Michael T. Flynn...but has not found any evidence of wrongdoing."
washingtonpost.com/world/national…
"Flynn...and Kislyak...are probably aware that Kislyak’s phone calls and texts are being monitored...That would make it highly unlikely...that the men would allow their calls to be conduits of illegal coordination."