Why did my manager blame me, then suddenly put my whole team on notice?

My TL told me I should resign. I documented and emailed my Operation Manager about it. Now they have decided to call me for a personal meeting... Told me I am at fault and try to improve myself... and the next thing I know the whole team is showcaused for bad performance. I didn’t get it. Why will the whole team get showcaused?
Why did my manager blame me, then suddenly put my whole team on notice?
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