no signal with external monitor
I have a macbook pro that runs catalina 10.15.6 (19G2021). I use a thunderbolt adapter to connect my external monitor to the mac. The problem I have is that it will intermittently work. Sometimes I connect the HDMI cable to the mac and the external monitor connects. More commonly however, there is a 'no signal' message on the monitor or both screens (mac and external monitor) go black. It is very frustrating as I would like to use the external monitor.
Any suggestions would be appreciated!!
Thanks