Dell E2720HS flickering as external MacBook Pro monitor I have an MBP 2012 model. I have Dell E2620HS and connecting it with an HDMI adapter via the Thunderbolt port. It has been flickering as it comes on and off.
I tried reconnecting cable but it didn't help. My OS is mojave 10.14.6
Edit: here is a video of flickering
Make sure that the HDMI adapter is compatible with MacBook. Some HDMI adapter isn't and makes your screen flicker.