I am getting this error as well. Everything has been working fine since I bought the TV in November last year. Now suddenly it cannot show or refresh the internet content. I have read numerous topics about it on the Sony forum and some external ones, but with no definitive answer. Many talk about problems with the Sony server in negotiating communication with an individual MAC adress. Some have claimed the problem solved by Sony staff inspecting the communication and then re-registering the client's MAC address on their server; after which the porblem is solved.
You say this is a speed issue. Is this definitive or could the network protocol negotiation be contributing.
I have taken your advice and tested my internet speed. My results:
Download 70.12 Mb/s
Upload: 0.51 Mb/s
Ping: 90ms
My symptoms are:
TV shows all connection tests ok (including internet).
TV shows no internet content and I get the 5006 error on internet content refresh.
I have access to local DNLA content servers on my home network.
Nothing has changed in the last week to my knowledge that could contribute to this.
I connect to my local network via a wired connection to a Netgear wifi converter. i.e. the TV is a wired connection although it is actually connecting to my network via wifi.