Issue with the syncing of my apple watch 6 and iphone 11

Hello everyone!

I just got my apple watch 6 from ebay. I have been trying to pair it with my iphone 11, however, I have not been successful at all. I have tried erasing all data from the watch, erase the network settings from my iphone, forced turned on and off the watch, but nothing has worked. The weird thing is that the pairing message that is supposed to show up on the phone has never showed up on mine. Does anybody know what the issue could be and what I can do? The watch is new. Thanks!