The article explains the difference between the following login pages:

Partner Portal login page

To manage your Partner account, you need to log in to the Partner Portal with your Partner credentials:

Parter Portal login

Read the Knowledge Base article on How Do I Reset My Partner Portal Password? for more information on how to manage your Partner credentials.

Account Contact login page

As a Partner, you can log in to any of your accounts from the Partner Portal > Customer Accounts > Active Accounts page by clicking the Login button next to the subaccout name:

Account login as a Partner

To log into the account directly, as the account contact, they need to use a separate login page - the account login page - and the account contact credentials for this account:

Account login

To find the account contact credentials, click on the Info button next to the account name and scroll down to the Contact Information section:

Account Contact credentials

Read the Knowledge Base article on Account Contacts and Contact Roles for more information.

Note: ShareSync Admin File Management is available only via the direct login as the account contact and is NOT available to the Partner logging in via the Partner Portal.

End-User login page

The end-user can log in to OWA or My Services via the end-user login page:

End-user login

Read the Knowledge Base articles on What Is Outlook Web Access (OWA)? How Does It Work? and How Can I Manage My Exchange Mailbox Using My Services? for more information.