My laptop ethernet connection won't start after I disconnect

I’ve posted on this problem before but I thought it was solved. But I am experiencing this problem again. I have a 2011 MacBook Pro (Broadcom network adaptor). When I plug the ethernet connection in, sometimes the connection works, and other times it doesn’t. When it does work and I unplug it to go somewhere, it doesn’t re-connect, especially if I connect to another network. Can anyone help me diagnose what’s going on?

Thanks,

Is Connect Automatically with Priority checked in network manager?

Thanks for the advice. I did check and the connect automatically with priority (set to 0) is checked. I changed it to -999 as you have here, and still no ethernet. When I enter the ethtool eth0 command, I get “device eth0 does not exist”.

Which Broadcom adapter? You haven’t posted any system information that might help others help you. Please read the following and post a full inxi output: