Hi there and welcome
Is the issue the TV will not see any wifi networks at all?
Or it does not detect the Dongle?
Can you please do a reset of the TV,
Go to Support, Self Diagnostics, Reset
Perform the reset and once done, tell me if it then sees the networks please
It is not just your network it does not see but none at all correct?
It is the dingle port that has faulted.
A corrupted firmware can cause this. But this has been ruled out by the reset. The Dongle itself has also been ruled out
I am really sorry about this and you are going to have to return the TV to have this replaced. It will be covered by the warranty if this has not expired, and the replacement will be done at no cost to you.
I am really sorry about this, and if you have problems, or would like any additional information or assistance, please do not hesitate to let me know.
And if you can take a second to rate my service by clicking one of the stars at the top of the page, then submit, that would be greatly appreciated.