My apple ID and password keep coming up as incorrect when trying to re-pair

I haven't used my apple watch in two years. I have since changed my apple ID username and password. When I log into apple using my ID credentials, my account still recognizes my watch. However, when I try to re-pair my phone and watch, it keeps saying my ID and/or password are incorrect (even though they are correct when logging onto apple and even though my apple account says my watch is under this ID). Help?