Help me! Thank ou

I think you probably mean "failed" (in the past tense) rather than "fail".

There is a present tense use of "fail" as in "words fail me" meaning I can't find the words to express the grandeur of this situation--good or bad.

"You fail me"--you have not met my expectations. You have not done what I asked of you. You have not done what I needed you do do.

Thank you very much!