[horde] IMP trying to expand all addresses?

[Peter Meier]

> When composing a message, IMP is reporting the following error upon
> submit:
>
> "There was an error sending your message: unable to add recipient
> [someone at gmail.com]: Invalid response code received from server"
>
> This doesn't happen if it's an address inside our own mail domain.
> Any ideas?

i think this comes from your local mta. so you have to check if this domain is
really usable through your mta.

i had also this problem, when our mta (exim4) rejcted an address 
because of some
access rules.

greetings pete