If you have the conversion URL embedded then you may want to delete it until AdCenter updates their certificate which expired yesterday. As of this moment customers receive a security warning at the point it is embedded- say at the "Thank-you" page. You may experience calls from worried customers whose confidence has been shaken by such a stupid mistake by MS.
Hi nefitco and everyone, The adCenter support team has confirmed that the security certificate issue is now fixed. If any of you are still experiencing this, please let me know. I'm sorry about this inconvenience.