My watch says its charging (green) then goes red. Its back and forth. I tried holding both Buttons and nothing happens, what can i do?

Make sure that the charging surfaces of the watch and the charging puck are very clean.

ASC - Late 2012 Mac mini, macOS 10.14.6; Watch, series 5 GPS/cellular, watchOS 6.2.8; iPad Air 2, ipadOS 13.6.1; iPhone 8+, iOS 13.6.1; TV 4th Gen, tvOS 13.4.8;  HomePods, audioOS 13.4.8 and Airport Express w/ Airplay 2