Unable to validate card


When I go to the card validator and put the url in, I hit preview card and get the following
"Unable to render card prview"

ERROR: Internal server error

I was prevously adding the meta data at the bottom of each post manually. But when I go to the validator now the only option there is to put the Card URL in - no option for the meta data.
The url I am trying to validate is http://fleetva.biz/perfect-business/. But this is just one, there are several I have tried to validate that won’t.

I have also tried JM Twitter cards plugin to work this out, but am getting the same response.


Is anyone able to help with this, I see there are others posting with the same issue. I tried another one today and got the same thing. This is the code I am using: