I think if you working on some internal product of a company, like management tool, sales CRM, etc. for that particular product you can use a subdomain of that company.
But if you are developing a standalone product you should go for the main domain. Though some app use subdomain for sign in and register process but they do because they have to use those credentials for different domains, mainly country-based like xyz.in, xyz.ae etc etc etc...
For further actions, you may consider blocking this person and/or reporting abuse
We're a place where coders share, stay up-to-date and grow their careers.
I think if you working on some internal product of a company, like management tool, sales CRM, etc. for that particular product you can use a subdomain of that company.
But if you are developing a standalone product you should go for the main domain. Though some app use subdomain for sign in and register process but they do because they have to use those credentials for different domains, mainly country-based like xyz.in, xyz.ae etc etc etc...