Comodo DNS problems

I have Comodo DNS, and have got problems with it today.
I can’t connect to Facebook or some pages. And with vpn, i can connect to them.
Because my vpn have another DNS servers. Maybe i should change to OpenDNS till something works with the comodo DNS?

Can you change the DNS servers as set in the VPN client? What happens if you set them to Comodo as well?

It was an issue on Facebook. You can close this thread now.
But, thanks for the help.