Normally this occurs when the GoPro camera is in an incompatible mode. First, ensure both the P1/R1/R1+ and your GoPro camera has the latest firmware installed. Then, make sure the camera settings are compatible: you can test this with the GoPro mobile app and compare the difference and check out the compatibility list here: https://removu.zendesk.com/hc/en-us/articles/360033977733-GoPro-compatibility-for-R1-R1-and-P1
In addition, the GoPro camera could also be defective if it's facing issues connecting to the GoPro smartphone app. Try reinstalling the firmware for GoPro see if that helps.
In some camera/modes, there will be no live mode while the GoPro camera is recording. We would recommend to contact GoPro support for further details.