Dead air call from a nonworking number.

Rang twice  no answer  non working number

Called and left NO Message!  When number is dialed, a phony busy signal is played until call is disconnected.  This clearly indicates that the call originates from a nefarious SPAM/SCAM entity engaged in number spoofing and other illegal activities, intent on defrauding people who may answer (calls made via cold-calling robo-calling boiler room frauds.)  DO NOT ANSWER!

Rec'd call from this unknown number; did not answer and no message left.