You can sign in to your Business Email account a few ways, depending on whether you'd like to check your email or manage your plan.
To check your Business Email:Sign in to your Business Email account at http://mail.yourdomain.com/
Note: Be sure to replace "yourdomain.com" with your domain name. You'll be prompted to enter your Yahoo! ID and password if you haven't already.
Business Email Welcome Message.
Welcome Menu: Address List
You can also check your mail from the Email Control Panel (Domains accounts will not have an Email Control Panel) or Web Hosting Control Panel (Domains and Custom Mailbox accounts will not have a Web Hosting Control Panel) of your Small Business account. Simply click the "Check Your Email" link or the "Check Email" button in the upper-right corner of the page.
Web Hosting Control Panel Check Your Email Button and Link.
Email Control Panel Check Your Email Button and Link.
Note: You will not be able to sign in to your mailbox if your domain is still pending.
From the Email Control Panel, you can manage every feature of your Business Email service — from editing your email address to checking your mail.
There are a few quick ways to reach your Email Control Panel:
Web Hosting customers:
Click the Email tab on your Web Hosting Control Panel.
Web Hosting Control Panel Email Tab.
Business Email and Custom Mailbox customers:
Sign in to your Business Control Panel and click the "Email Control Panel" link associated with your plan.
OR
Sign in to your account at http://mail.yourdomain.com/
Note: Be sure to replace "yourdomain.com" with your domain name. You'll be prompted to enter your Yahoo! ID and password if you haven't already.
Business Email Welcome Message.
Welcome Menu: Address List
Mail Options Menu: Administration
Business Email Administration: Manage Link