I tried to make a call to my cell phone, it rang for 60 seconds but my cell never rang. Then I made a call to my Vonage phone, it rang right away. Then I made

I tried to make a call to my cell phone, it rang for 60 seconds but my cell never rang. Then I made a call to my Vonage phone, it rang right away. Then I made another call to my cell, it rang right away. Not sure what this means, perhaps they have some kind of special SIP routing setup?