Trial and Licensed Acterys users have access to the full knowledgebase. If you can't login with your business email address please follow these steps.
Click on "Create Ticket" and request access for your business email address (eg. xxx@microsoft.com):
This is not to be confused with the Acterys AD user e.g. xxx@acterys.onmicrosoft.com that can't be used for access to the knowledgebase.