My ethernet cable internet has stopped working. I normally connect my 2013 MBP to the internet via my home wifi network, however I often like faster internet for downloads, games, etc and connect using an ethernet cable and a thunderbolt adapter. It has stopped working. Normally I have to turn off the wifi to force it to use the ethernet (not sure why!?) but that makes it work. This time that doesn't work and diagnostic/assistant doesn't help either. The wifi works on the same network. The ethernet cable and port works on a different laptop (I haven't checked the thunderbolt adaptor because it's not a mac). Why would it stop working (I haven't changed anything)? How can I fix it?