My custom login URL for email is working fine

the problem I see is that when a user logs out, it does not return to the same custom URL login page which in my case is mail.mydomainurl.com

it instead logs the user out to:  https://mail.zoho.com/biz/customlogin?rd=mail.mydomainurl.com

This is not a good way to keep my users on one page for login and logout

is there a way to fix the "exit page"?

Once user logs out of email, have him/her go back to our custom login URL?

please help

Thanks