Nkc-135a

I have just read an article in AFM saying a USAF NKC-135 has not been allowed to fly over France while en route from Mildenhall to Souda Bay during March!

This is the first time I see this kind of incident between two allied european countries!
What could have done this a/c “53132” before, not to be allowed to use standard civilian traffic airways over this country?

Does anyone know about this case?

Thanks!