We just finished the roll out to address the root cause for the board and sprint issue.
The current status is that the root issue has been addressed and functionality for your boards and sprints has been restored.
If you have any additional concerns or questions, please do not hesitate to let us know. statuspage
Also, in the future, major issues/outages are communicated in our Status page, status.atlassian.com
Backlog and Active Sprints links are missing in JIRA Agile when using the new Project Sidebar
Not able to see Active and Backlog Sprint option from Left Navigator for JIRA Software