Keep the successful local test
A local file playing shows that VLC can open that file through the local route on that computer. It does not establish that a remote media address is reachable, that access is authorized or that its encoded tracks match the local file. Those differences are the useful starting point.
Avoid reinstalling immediately if the application is already functioning with local media. Record the application and operating-system versions, then identify how the network source was entered and at which stage it failed.
Use the documented network control
In the desktop interface described by VideoLAN, the Media menu provides Open Network Stream. The Network tab accepts the network-media address, followed by the playback action. Use the instructions for the actual VLC platform and version; menu presentation can differ across operating systems.
A network-media address is not a universal portal or OTT account field. Enter only the legitimate source format supplied for the intended route. Do not alter a password-bearing address publicly or guess new paths from a failing value.
Compare the stage and format
Note whether VLC rejects the input immediately, waits without opening, shows an error after loading or begins playback before stopping. If media information is available, compare the actual tracks rather than the file extensions alone. Sound without picture is a different symptom from the source never opening.
A useful report can state that a named local file works while the specified authorized network item fails at a particular time and stage. Redact the full private URL. This preserves evidence without assuming that the local success proves the server, network or account must be correct.
Questions answered
Does a working MP4 file prove a remote playlist will play?
No. The source, access route and encoded media can differ.
Can I put any portal address into Open Network Stream?
Use the media-source format documented for VLC and confirmed for the actual service.
Sources & further reading
Official references for the subjects discussed. Service terms and device software can change.