。
I'm aware of your failure.
Literal
Your failure [topic-は] acknowledged.
不首尾 (ふしゅび, 'failure, poor result') is formal vocabulary. 承知している ('I am aware of, I acknowledge') is the polite/formal way to say 'I know.' The sentence is terse and authoritative — a superior addressing a subordinate. The は topic-marks 不首尾 as known information, while 承知している confirms the speaker's awareness without judgment (yet).