There is now a dedicated Twitter for Server Status. https://twitter.com/RL_Status

Parties may get destroyed on Tuesdays because of Steam maintenance.

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If servers appear to be down, check https://steamstat.us/ , https://status.epicgames.com/ or https://twitter.com/RocketLeague

"Steam is down for routine maintenance every Tuesday."

This can cause issues with creating/joining/preexisting parties. Can also affect the Match making service. There is no way to tell when the maintenance will start or when everything will become stable again.

We will send out an official Steam announcement if there is actual Rocket League server maintenance.