iWatch series 1 is not pairing
My iWatch series 1 is not pairing with my iPhone 6s plus and I've tried restarting both devices and nothing happened. Also, I used reset on iWatch and erased everything and nothing happened.
The 6 digits number is not showing for some reason and my iPhone is up to date (13.2.2) and did reset to network settings and same thing.
Please help.
p.s. both devices were paired long ago but now not.