Guys I'm facing a prob here. I connected my macbook to external monitor for sometimes ady, but yesterday dunno why suddenly there is discolouration(light blue) on the external monitor. I can use everything normally, just that now the background has light blue discolouration which is very irritating. If I change back to macbook screen, eevrything is normal. It only happens when I use external monitor. Anyone has any idea how to solve this problem?

It's a new monitor boss, tried another cable. same result... Any other solution?