That view in question from your screenshot, is the Release report. The release is scheduled to end in another 23 days because the work assigned to a release is larger than the available team capacity, and this makes the release turn red.
In this release report view, the capacity is calculated using the team's velocity and the scheduled work for the release. For example, the team can finish a maximum of 30 story points in each sprint, the capacity will be overloaded if the work assigned to a release that has a fixed end date sometime in the next sprint are estimated more than 30 story points.
Some additional details on the settings can be seen in:
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