On our old site, we had a page www.domain.com/contact-us/ which doesnt exist anymore. No we have www.domain.com/contact/ But Google tells, www.domain.com/contact-us/ was the famous page with good domain authority, so we tried to edit the permalink for www.domain.com/contact/ to contact-us , but its saving as contact-us-2 I searched for www.domain.com/contact-us/ on frontend and backend, but it doesnt exist, so why does it not accept contact-us ? Is there a way to search this on database and delete the contact-us record, then it will accept ?
I think contact-us page is still save somewhere. Search in deep and you will find it. You can check it in Menu or Pages option of WordPress. After removing it you can make a new page with this name.
The old contact page is most likely in the trash. Change the slug of the old page or delete it permanently. You should then be able to change the name of the new contact page.
Check: whether any page or post with this slug exist in the - 1) draft 2) trash Search separately in Page list and Post list thoroughly.