Moved my blog to a new domain and now comments do not work

Hello,

I moved my WordPress blog to a new domain and everything except comments is working properly.

Whenever I try to submit a comment I receive the following error message: “Unable to resolve the server’s DNS address.”

I suppose that this is happening because there is a pointer somewhere to my old domain, that is not active anymore.

Any hints on where should I check for this reference to my old domain?

Thank you all in advance.