This issue occurs because  your TV does not support the higher resolution.

STEP 1

Switch off the power for your box and make sure that the adapter’s power light is off.

STEP 2

Switch on the power for your box and make sure that the adapter’s power light is on.

STEP 3

Press the standby button repeatedly after switch on the power.

The Startup Options screen will appear on your TV.

STEP 4

Press ‘987’ to access the Advanced Startup Options menu.

Then, press '1' to initiate a reset setting.

STEP 5

Press "OK" to confirm restore to factory setting.

STEP 6

After the factory setting is restored, TV will turn blank.

Please wait until the box completes initiate setup.

STEP 7

Press "1" to initiate Linux download on the software.

STEP 8

Once completed, the following screen will appear on your TV.

Refer to Installation Setup guide here to complete the setup.