These steps above should get you on the right track with MoCA. Specific to the goCoax adapters - are you connecting the MoCA adapters to 2.5GigE devices? If so

These steps above should get you on the right track with MoCA. Specific to the goCoax adapters - are you connecting the MoCA adapters to 2.5GigE devices? If so, the goCoax adapters have an (unfortunately) not well-known-enough issue where you need to disable EEE/Green Ethernet to get a stable connection with some devices. Screenbeam makes a MoCA adapter that doesn't have this issue, the ECB7250S02, and goCoax claims to have a firmware without EEE enabled on the adapter side if you email their support email as well.