Help with connection

[jmillican 0]

I have a small business using a avr-th908e server connected to a wgr614v9 router getting internet from dsl. I can view cameras in store fine wired and wireless. The problem is on my mobile on a different wifi network I can’t see my camera with mviewer pro. The mviewer open like normal but does not show pictures. If turn off the wifi connection and use att 4g I can see my cameras but it runs up my data usage. My question is what could be the reason for not seeing the cams on wifi but seeing them on cell service.

Thanks for any help

JM