That looks nasty, it is not normal. I don't know about the fluid inside, but that brown gunk around the cap is an unhealthy dose of rust/leak sealer. The OEM coolant should look pinkish but pretty transparent and "watery", not thick at all.
How long since you bought it and how long since you are getting problems?
I would test for a gasket leak first, put a latex glove on the reservoir hole and see if it blows up. Are you having overheating problems? Bubbles in the coolant fluid? White smoke out the exhaust?
You could also bring it to a workshop so they can do a coolant system pressure check to diagnose a gasket leak.
Anyway, after you're found what the issue is, you need to clean the whole coolant circuit since that gunk may have partially blocked the radiator. Drive it with plain water through multiple heat cycles, drain through the bottom radiator hose and repeat. I succesfully cleaned mine using citric acid solution, more info here:
https://www.jeepforum.com/threads/ov...og-it.4478571/