Unable to pair my Apple Watch Series 6 to my iPhone 8

I just bought this Apple Watch 6 and tried to pair it with my iPhone 8 Plus but I keep getting an error saying my phone is out of date, however, when I look it up, the apple website says it works with the 8 plus. My phone is currently on 16.7.10, which is current.

Am I doing something wrong?

[Re-Titled by Moderator]