a browser page, video, presentation, or game cannot enter fullscreen
This symptom concerns the system path. Start with a neutral DeviceOK test where available so the next step is based on evidence rather than a generic reset sequence.
Do not jump to the most invasive fix
Avoid destructive resets, unofficial driver packages, firmware flashing, or replacing hardware before the simpler detection, permission, connection and configuration checks are exhausted.
Retest the same condition
After every meaningful change, repeat the same test under the same conditions and compare the result.
Rule out the simple causes
- 1
Run DeviceOK Fullscreen Test from a normal tab.
- 2
Exit any existing fullscreen/Picture-in-Picture mode and retry.
- 3
Make sure the action is triggered by your click rather than an automatic script.
Work through the problem in order
- 1
If DeviceOK enters fullscreen, focus on the affected site's player or embedding restrictions.
- 2
If fullscreen is unavailable in an embedded frame, open the content directly.
- 3
Browser or device policies can also disable fullscreen.
If the matching DeviceOK test succeeds, prioritize the affected app, browser policy, operating-system setting, or configuration before assuming complete hardware failure.
If the same capability also fails in DeviceOK and another trusted diagnostic path, broaden the investigation to connection, operating-system/device state, official driver or firmware support, and finally hardware.