If KRNL-Injector failed to find the Roblox process, delete KRNL App data and see. If that doesn't help follow the solutions mentioned in this post to resolve the issue.

Nefarious game makers appear to be leveraging a chat-based Roblox exploit that results in automatic account bans for unsuspecting users.

Roblox is implementing fixes for a chat moderation exploit that resulted in a wave of automatic bans, but the offenders say there’s more to come.