Three related terms: 封禁 (formal, 'ban / block'), 封号 ('ban an account', more colloquial), 禁言 ('mute / silence' a user without removing the account). Platforms also use 永封 (permanent ban) vs 短期封禁 (short-term ban).
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Slightly formal/journalistic. Tech platforms and news articles use 封禁; in everyday chat among users 封号 is more common (我号被封了 — my account got banned).