e-mail security settings via custom form not being applied
 

I have two domains and two networks that are trusted and for all intents and
purposes allow for seemless traffic flow. I can logon to domain 1 when on
domain 2's network/subnet and vica-versa, etc. The one caveat presently
being experienced is the ability to send email from a problem ticket tracking
system when connected to domain 2, logged onto domain 2, but using an
exchange account on domain 1. I get prompted to authenticate to access the
mailbox which is expected and can send messages, but the Outlook Security
Settings public form settings are not being applied - I get the two prompts
to permit the email action. With the exact same scenario, but only changing
that I'm connected on domain 1's network (still logged onto domain 2) I can
send without prompt - the form is being applied.

Any thoughts on how this could be resolved would be much appreciated.

Cheers!