APP Error: “check the input source” Hollyland Tech March 01, 2021 08:20 Updated The MARS systems use the general 5g WiFi network, and the WiFi network created does not have a network connection. When connected to WiFi without a network connection, it will automatically switch to data cellular or another WiFi for some Phones. So you will get the " Check the Input Source" Error from HollyView App. Solutions: Confirm the OLED screen of the MARS 400S PRO has the Video Format Display. Allow the Location for the HollyView App under iPhone settings. Make Sure the "Connect" Button on the HollyView App is Yellow. Turn off the cellular data on the Phone Settings. Use the cellular data at the same time when using HollyView APP: Related articles How to do the App Connection？ Why I can’t get the video format on the OLED screen ? what kinds of MARS series products support 1 transmitters to 2 receiver? How to add my own LUTs to HollyView App? How to pair a new RX with the current system ? Comments 0 comments Article is closed for comments.