Same issue as user btp, using latest firmware for DCS-942L, Tmobile, IOS 10.2 on both iPhone and iPad, and Dlink Lite app version 3.6.7. (Worked fine with older firmware, IOS 9, and older Dlink app)
If connected via WiFi it works, If Cellular it gives error 0.70_0_2_7_70. (what ALSO does not work is viewing live video on a Mac running OSX Sierra using either the OLD plugin linked to one the live video page, OR the newer plugin I found on some Dlink support page.
But here is what DID work when using cellular... connecting the iphone or ipad via a VPN service such as private internet access. Doing this eliminates the cellular <> dlink connection, going through the VPN instead eg Cellular <> VPN <> Dlink
It's not a practical workaround unless you already use a VPN service, but it does seem to prove that Dlink is not handling the data traffic correctly to be compatible with the cellular carriers.