I have seen the previous posts about this and have followed them but it didn’t work. Particularly this seemed really promising until it didn’t work :]
I have a 2015 MacBook Pro that I use with an external monitor till last week. All of a sudden the monitor doesn’t work and instead gives me a “Invalid input error” message. It still works when the laptop lid is open though. I was using 10.15.3 when I saw the error, then updated to 10.15.4 and still doesn’t work. Anyone else seeing this error? Its driving me nuts.
I also tried a MacBook Air and it works fine. So at least I know the display is working fine and the issue is with the MacBook Pro.