How to Remove Slug From Database?

For example:

• mydomain.com/embed automatically redirecting to homepage although I
  haven’t set redirection.
• I want to add a page in my website name embed and for this page URL
  automatically becoming mydomain.com/embed-2.

I checked everything, there is no existing or trash post, page, tags Etc.

How to remove that existing embed slug from the database?

Thanks

I don’t exactly know about the word embed, but by default WordPress reserves & uses these sort of words for internal use. I tried to create a page slug named embed but it wouldn’t work for me either on my localhost or on my live server. Maybe this is reserved for WordPress oEmbed functionality.