Blackboard Learn was designed initially for use with Google Chrome. Chrome allows certain Java to function as needed. Some browsers such as Safari have limited their ability to use Java, and consequently, limited their use with Blackboard.
Download link:
https://www.google.com/chrome/
How to set Chrome as your default browser:
https://support.google.com/chrome/answer/95417?co=GENIE.Platform%3DDesktop&hl=en