Fan Fic or not, it's not a reason for a poorly made movie.
It's like they haven't read any of the books, don't know the characters and just wanted to use the popular names to make their own bad movie!
To argue that point though, is that there is actually an Enola Holms book series, and the film is probably based on that.
https://www.google.com/search?q=enola+holmes+books&rlz=1C1CHBF_enTH843TH843&oq=enola+holmes+bo&aqs=chrome.1.69i57j0l7.7390j0j7&sourceid=chrome&ie=UTF-8Following below are cases where the Conan Doyle Estate had attempted to sue movies/ books based on Sherlock Holms on two occasions, where the story have been mostly ruled out as public domain material.
"First, the Conan Doyle Estate at least seems willing to admit that the earlier works are now fully in the public domain:
"
The first fifty of Conan Doyle’s Sherlock Holmes short stories and novels are in the public domain." As referenced in the case where the Conan Doyle Estate had sued the author,
Mitch Cullin, who wrote the book
A Slight Trick of the Mind about a decade ago, and that's now been adapted into a film called
Mr. Holmes, being released by Miramax.
Also in reference to another case: Enter
Klinger and
“In the Company of Sherlock Holmes,” the pending anthology he coedited with Laurie R. King. The anthology, coming from Pegasus, collects
new stories inspired by (and including) Sherlock Holmes from writers Michael Connelly, Cornelia Funke, Harlan Ellison, Jeffery Deaver, Sara Paretsky and more.
Klinger brought suit against the estate, arguing that Sherlock Holmes and the other familiar elements of his stories — sidekick Dr. Watson, nemesis Moriarty, the famous lodgings at 221B Baker Street — should be free to use.
“Sherlock Holmes belongs to the world,” Klinger wrote on his Free Sherlock website.
First U.S. District Judge Ruben Castillo found in favor of Klinger. That was in December; in June,
Seventh Circuit Judge Richard Posner rejected an appeal by the Conan Doyle estate, siding with Klinger.References:
https://www.techdirt.com/articles/20150524/17521431095/sherlock-holmes-case-never-ending-copyright-dispute.shtml#:~:text=The%20first%20fifty%20of%20Conan,copyright%20in%20the%20United%20States.&text=The%20works%20still%20under%20copyright%20delve%20into%20it%20much%20more.
https://www.latimes.com/books/jacketcopy/la-et-jc-sherlock-holmes-public-domain-20140805-story.html