An old address is not the film itself
A bookmark may contain a site's own title number, a player path or a domain that no longer behaves as it did when you saved it. Begin with the film or series name if you can recover it. A release year, actor or episode title can settle the remaining uncertainty. Search NetFilm with that information instead of expecting another website to understand an old internal number.
Netfilm.app and other namesakes
Questions about what happened to Netfilm.app refer to an earlier service and its history. Current addresses using NetFilm or a similar spelling are not necessarily operated by the same people. NetFilm is also used by unrelated products, and it is not an abbreviation that grants access to Netflix. This page does not certify an official successor or a live network of backup mirrors.
When the address does not open
Check that the address has been entered correctly, then establish whether the failure is limited to that page or affects other websites as well. If the catalog opens but a viewing offer does not, check the viewing country and the destination separately. These are different problems and need different observations. An endless sequence of guessed domain endings is less useful than keeping the exact title you were trying to find.
Use title search to recover a production, alternatives to compare a new viewing routine, or troubleshooting to work from the symptom you can see.