I get those error messages all the time in my SB5100 here in south Florida. They're nothing to worry about. Someone here or on another forum said they'll go away once Bedrock is fully implemented.
I never even noticed the outtage caused by the Comcast DNS servers going down last night. I've always found their DNS servers slow, so I've pointed my router to off-network DNS servers, which I've never had a problem with. A number of alternative DNS server addresses can be found here: https://testmy.net/topic-4249