My iPhone 12 is not getting paired with my apple watch 5

Team,

I got my iPhone 12, approx 2 weeks back and since then I'm not able to pair my apple watch 5 with this new device. iPhone is not detecting iWatch itself. I tried manual approach too but no luck.

I also tried to pair my iPhone 12 with iPhone 11, but every time pairing was unsuccessful with a message "Make sure "abc" is turned on, in range, and is ready to pair."

Please help me out at the earliest.