Attributes not allowed here

Hi –

I’m using your plugin on a client site (http://www.bigfootservices.co.uk) and when I run a site analysis tool (http://nibbler.silktide.com/) I get the following two errors:

Attribute xmlns:og not allowed here.
Attribute xmlns:fb not allowed here.

Any help you can provide to resolve this would be very much appreciated…

https://wordpress.org/plugins/wonderm00ns-simple-facebook-open-graph-tags/