Record the point where playback changes
A useful observation is that a film plays on the computer’s own display but fails after an external monitor, projector or television is connected. BFI’s help discusses “Video not supported” or Error 4 in relation to updated security requirements. The comparison identifies a display-path question; it does not prove that the film, account or broadband service is generally unavailable.
Follow the documented connection checks
BFI directs external-screen users to an HDCP-compliant HDMI connection and suggests testing another television port or a direct connection that bypasses a dock. It says VGA is no longer supported for this purpose. Check the actual accessories in the path, including an adapter or hub, rather than assuming a new HDMI cable proves every intermediate component meets playback requirements.
Keep operating-system guidance specific
The same help page gives distinct secure-playback advice for Mac and Windows, including trying Safari on Mac or Edge on Windows. It also now says Linux-based systems are unsupported. These are BFI Player’s documented conditions, not a universal statement that other browsers or Linux cannot play any online video. Use the current first-party instructions for this particular service.
Change one part and retain the result
For example, compare the same film on the built-in screen, through the dock and through a permitted direct connection. Record which route works and whether the error text changes. That evidence helps support identify the relevant stage without a broad factory reset. Do not purchase replacement equipment solely from an error number; first confirm the actual device and supported connection requirements.
Questions, answered
Does Error 4 always mean the subscription expired?
No. BFI’s guidance includes secure-playback and external-display causes.
Is a VGA connection still a supported route in that help?
BFI’s current help says it is not.