Why is ETH not showing up in MetaMask?

I've been scratching my head over this issue for quite some time. Can you tell me why my ETH balance isn't reflecting in MetaMask? I've double-checked the wallet address and everything seems to be in order. Could it be a network issue? Or maybe I'm missing some crucial step in the process? I'm a bit new to this crypto world and I'm still trying to wrap my head around all the nuances. Could you please help me understand what might be causing this and how I can fix it?