Can't send MacMail email when Secureline VPN on due to virtual ip address

Hi
My US email provider, optimum.net, does not like the 89.x.x.x virtual address (Romania) “unable to accept email from my location”. I put mail.optimum.net in my “trusted networks” and have checked “Exclude trusted networks” but optimum still sees my virtual address. Why doesn’t it see my non-virtual address?

Mail works fine when VPN off and incoming mail works fine with VPN on.

Is there a way to tell Secureline VPN to use a US address (or a particular high level address) as the high level address? If not, do I need to change email providers?

Incoming mail is fine with VPN on.

Running MacOS Catalina 10.15.4 and Mac Mail 13.4
Thanks.
Ray