arduino yun connect to 4g mobile(hotspot)

Hi,

We have successfully connected arduino yun to our wireless router at home, and we can access it via ssh on pc and see it on tools->serial port, the weired thing is: when I connect ed yun to my 4g mobile phone's hotspot, I still was able to ssh it from my pc, but on arduino ide->tools->serial port , it greyed out without any port items, any advice would be appreciated.