Validator tool shows Invalid Card Type all of a sudden


Validator says 'Invalid Card Type’
Sample URL:
Sample Tweets: /
What’s in the page source:

<!-- Twitter Cards -->
<meta content='summary' name='twitter:card'/>
<meta content='MisterJonjon' name='twitter:site'/>
<meta content='' name='twitter:domain'/>
<meta content='LG Electronics (LG) today announced the LG G Pad 8.3 tablet, the latest addition to its G Series lineup of premium mobile devices.' name='twitter:description'/>
<meta content='jonjongoco' name='twitter:creator'/>
<meta content='' name='twitter:url'/>
<meta content='LG G Pad 8.3 with 1920x1200 display goes official' name='twitter:title'/>
<meta content='' name='twitter:image:src'/>
<!--- End Twitter Cards -->