When I plug in my HDMI cable and want mirror screens to watch a movie on my TV I just get a picture of my background and in the bottom left corner comes a cog and in the bottom right side there are a lot of dots in a square but no more if I go over to HBO on the phone and start a movie then only the sound comes on the television but no movie only the same pictures that have always been when I start mirror screens
what to do?
why new cable? the one i have is also usb-c i can use dex on the computer screen so i can write on the computer, so i should also be able to see screen mirror with this cable?
i fix it by a totel reset to factry
I had a similar issue and found a fix. In my case I had enabled developer options in settings and had turned on Force Desktop Mode. Once I turned it off again the HDMI mirroring worked as normal when I turned off Dex.
See the picture below for how it should look:
Disconnect the HDMI cable from the HDMI Output terminal on the connected device. Reconnect the HDMI cable firmly to the same terminals as before on the TV and the connected device. Turn on the TV and the connected device, and turn them off. Then turn them on again to let the TV recognize the connected device.