Can't send mail from kontact using davmail

I moved to Arch Linux recently with KDE, and tried setting my organization email account on Kontact using davmail.
It's not my first time, and I just used this steps as usual:
http://osdir.com/ml/kde-pim/2011-07/msg00146.html

Everything was setup except I couldn't send email and received the following error:

Error : davmail.exchange.ews.EWSException: ErrorSendAsDenied The user account which was used to submit this request does not have the right to send mail on behalf of the specified sending account

After lot of investigation, I found out that somehow "davmail is not sending the right "From" address in new versions".
That's Ok, except I have an old davmail server, that wasn't updated for some months, and it worked before I moved to Arch.

So I tried to check the Kmail side, and after a lot of time, came up with this note in the documentation:

The way of sending messages configured here will be used for your default identity and for all other identities that do not have their own way of sending messages. You can use different ways of sending messages for different identities by selecting the Outgoing Account check box in the Advanced tab of the Identities page.

Kmail Identity settings

Let's check my identity then! And I've found the culprit.
Go to Configure Kmail ->  Identities -> Choose your Identity -> Modify.
I had no email address set in my Identity, right after setting it up, the emails sent successfully!

Not sure why it happened, maybe some change in the newer version of Kmail. But that fixed it for me, and hope does the same for you!