I have the same problem, except with my SURFACE 2.
The TV is a Samsung UN55H7150 - Brand New.
The WPS screen showed up and I added the code to the surface. Now, it just sits there with the 'Connecting to SURFACE 2' message on the screen, and then eventually times out.
Both Surface 2 and TV are on their latest firmwares / updates.
the only Miracast certified Samsung TV's are the Echo-P Series TV.
There is no guarantee that an uncertified TV will work. Samsung DOES NOT CERTIFY THEIR TV'S. Their TV's don't fully support the Miracast standard.
Regardless, MS is going to have to develop a work-around since Samsung HDTVs are among the most common TVs and shooting the SP3's screen to an HDTV is a big selling point.