Sony Bravia KDL-70W850B I-Manual page 223

Check the installation location of the TV and wireless router (access point).
Signal condition may be affected for the following reasons.
- Other wireless devices, microwaves, fluorescent lights, etc., are placed
nearby.
- There are floors or walls between the wireless router (access point) and
TV.
If the problem persists even after checking the above, try making a wired
LAN connection.
The TV cannot connect with your wireless router (or
access point) at 5GHz.
While [Wi-Fi Direct] is set to [On], you cannot connect to a wireless router
(or access point) at 5GHz. Set [Wi-Fi Direct] to [Off]. Press the HOME
button, then select
Poor picture on Internet Videos.
Quality depends on the original video provided by the video content
provider and your connection bandwidth.
Certain Internet video content displays a loss of
detail.
Video quality and picture size depend on broadband speed and delivery
by content providers.
Good picture quality but no sound on Internet video
content.
Quality depends on the original content provided by the video content
provider and your connection bandwidth.
Due to the nature of Internet video, not all videos will contain sound.
Apps are inaccessible.
Check that the LAN cable or AC power cord of the router/modem* has
been connected properly.
* Your router/modem must be set in advance to connect to the Internet.
Contact your Internet service provider for router/modem settings.
Try using apps later. The app content provider's server may be out of
service.
[Settings] → [Network] → [Wi-Fi Direct] → [Off].
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