Register with @customdomain.com redirects to unknown SSO

We're trying to create accounts using the @learningheroes.com email domain (our company domain), and we're not able to create the account.

Once we try to create it using the Zoom Web App it redirects to calliduscloud.zoom.us SSO, a company unknown for us, that we never heard or have any knowledge about it.

We have not configured SSO for our domain and as I'm the IT manager for the company, in our DNS records for our domain we have nothing related to Zoom verification for SSO.

This url is a small video of what is happening.

https://gyazo.com/8ed51ff2898c632c282868860f04150d

Any help is welcome!

Thanks!