A Europol report suggests that national law enforcement authorities are often unable to obtain 'e-evidence' from digital service providers due to filing their requests incorrectly.
“The planned EU e-Evidence regulation is intended to force Internet service providers to cooperate more with police and judicial authorities. However, a survey shows that the companies already comply with their requests voluntarily. But they are often incorrect and thus rejected.”
See: Europol Study: Disclosure of electronic evidence often fails due to incompetence of authorities (Matthias Monroy, link)
And: Europol: SIRIUS EU Digital Evidence Situation Report 2019: Cross-border access to electronic evidence (pdf)