The most common and most likely answer to this crossword clue is the 8 letter word VIOLATES
I've seen this crossword clue in Financial Times
V
I
O
L
A
T
E
S
Buddy explains!

The straight part
We know that "Fails to comply" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case fails to comply = violates.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does VIOLATES mean?
VIOLATES verb- To break or disregard (a rule or convention).
- To rape.
- To cite (a person) for a parole violation.