公式によるとRealmsとかマケプレとかオンライン関連が少し前まで調子悪くかったけど対処したのでそのうち直るだってさ

Mojang Status
@MojangStatus
·
6時間
We are aware of issues causing downtime for services including Marketplace, Realms, Servers, and inviting friends. The team is actively working to resolve the issues. -MG

Mojang Status
@MojangStatus
·
5時間
Services have started to stabilize and should once again be accessible. Thanks for your patience and now we can get back to mining and crafting! -MG