We have our 4G home internet set up and have installed 3x CPE220. One AP on the roof directly feeding into the modem and 2 setup on external buildings on our property as clients. We just recently installed one the 2 clients and since doing so it has been causing the modem to disconnect and not pick up 4G internet signal.

We have a Huawei B818 modem/router which is what the AP is connecting to. Does anyone have any suggestions on what to try or what has worked for them? 

We have a TP Link router that we are wanting to setup as an AP at one of the out buildings and if that works we will do the same with the other client.