Leica R62 ight meter won't work during the day

So I've noticed that in the dark the meter gives me a correct exposure, however while I'm out in the sunlight or even if I turn on a bright light in my bedroom then the red circle will flash signaling an incorrect exposure or improper lighting. It's definitely not the batteries, but it could be the contacts? I'm not experienced enough to solve this one on my own, but hopefully it's something simple to fix. I'm spot metering if that helps, and without a grey card. Is a grey card a necessity?

If you have the cardboard from a legal pad or such, it'll be close. Since you're checking for a ballpark valueIt doesn't need to be a grey card to check a meters response unless you're trying to be accurate.