Problem with DNS of Comodo Firewall and Exchange

Hi all,
I have installed Comodo Firewall but when use the DNS of Comodo, the Outlook Exchange don’t syncronize the folder and new email.
The problem is using the Comodo Firewall DNS does not resolve the domain’s mail server xxxxxxx.com
My laptop is not connected to domain but uses only the client exchange
Now I removed Comodo Firewall DNS and restarted the network card and exchange outlook has started to function again.
There a way to run Exchange also using DNS of Comodo Firewall?
Thank you for your support.
Tano

Is the Exchange server local to you, i.e., on the same network?