Blackout
A period of time when services are inaccessible or restricted e.g. change blackout, system blackout, blackout period, blackout days. A media blackout refers to censorship.
Why it matters
Moving away from terms which infer positive or negative connotations associated to colour and colour binary (e.g. Black = Bad and White = Good) to distance from cultural views of good & evil, especially related to skin colour or appearance. Specifically, this associates 'black' with a blocker of progress, improvements and change.
Instead try saying:
Further External Reading Link