The CONNECTION Client is your gateway to Bentley's cloud services, portals and analytics. By signing into the CONNECTION Client you can find your company's projects, track your time, explore analytics, download software updates, receive relevant notifications, and access other features available to you as a Bentley user. Signing into the CONNECTION Client is a prerequisite to participate in CONNECT capabilities provided through your Bentley desktop applications (CONNECT Edition or V8i with CONNECT Services).
https://communities.bentley.com/products/microstation/w/microstation__wiki/26855/connection-client-user-failed-to-login
Training: Understanding the CONNECTION Client as a CAD Administrator
https://learn.bentley.com/app/VideoPlayer/LinkToIndividualCourse?LearningPathID=111447&CourseId=121246&MediaID=5013819