Problem
Blackboard reports that there is a DNS error and some users may not have access to the Blackboard website.
Solution
All users should try the following to resolve this issue:
Please try to clear the cache in your internet browser (Safari, Firefox, Internet Explorer).
If the issue persists, try another browser.
If the issue persists, restart your computer/device.
If the issue persists, follow the linked guide to clear your local DNS cache.
Related CIT Known Issue(s)
https://cit.ua.edu/known-issue-blackboard-server-error-april-25/