Iphone 12 Pro Max - Facebook not linking to Instagram

Just got my new Iphone 12 Pro Max. My business Instagram Post is not linking Facebook. I manually click on the Facebook button before I am about to post through Instagram, but the button doesn't turn BLUE. I've logged out of both Facebook and Instagram, and even changed my passwords for both apps. I never had this problem on my Iphone X. Not sure if this is the forum for my problem, but it is becoming very frustrating... Hope someone can shed some light on my problem.