Nighthawk Router keeps dropping service.

I’ve had 3 techs come out. And still keeps dropping. Any ideas? Keep getting this on the log. And then it times out.

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=08:36:c9:ce:a2:c8;CMTS-MAC=00:01:5c:82:fc:4b;CM-QOS=1.1;CM-VER=3.1;