First establish whether the control exists
Open the genuine Roku app’s Remote view while connected to the intended Roku. Check the mobile app version and update through the normal store if appropriate. Roku explains that an old app or a Roku without mobile Headphone Mode support can account for a missing icon. Verify the exact product rather than assuming every device with the Roku name has the feature.
If several Rokus are listed, select the one actually producing the picture. The phone can control a bedroom device while you are watching a living-room television, creating a misleading comparison. A clear local name for each device helps prevent that confusion.
Look for a competing headphone path
Headphones plugged into a compatible Roku remote displace mobile Headphone Mode. If several listeners suddenly lose phone audio when someone inserts a remote headset, that sequence is useful evidence. Choose one listening arrangement for the session.
For a Streambar or Roku soundbar, also identify whether the programme is coming from its built-in player or from an external device. Do not use the same symptom description for an app playing on Roku and a console feeding audio through the soundbar. Their supported paths differ.
Interpret a restart at activation
Roku documents a stop-and-restart when Headphone Mode is enabled during an already playing video, as audio and picture are synchronised. Try activating the listening route before starting the programme. A single restart at that transition is different from repeated stops throughout playback.
Once the mode is active, observe a complete short passage without changing outputs. If it keeps stopping, record when and whether the normal speaker route behaves differently. This establishes an actual recurring symptom rather than treating the initial switch as a sustained streaming fault.
Report the first failing stage
Describe whether the icon is absent, headphones connect without sound, another output interrupts them or the sound has a fixed delay. Include Roku and mobile app versions, the active source and headphone connection. Do not include the service password or playlist.
Only pursue audio-delay adjustment after you have a stable output session. Changing timing cannot make an unsupported feature appear, and repeatedly resetting a service account does not resolve a remote socket taking over the headphones.