To answer your question I will need to make a couple of assumptions. I am assuming that this is the first time you are setting up the email in Outlook. That you have our standard email forwarding package and all the emails we send go to the Yahoo address
If that is the case then it is the Yahoo email address is the one you have to enter and set up in Outlook. It is also Yahoo’s SMTP details which you need to use which are:
Incoming : pop.mail.yahoo.co.uk
Outgoing : smtp.mail.yahoo.co.uk
Once you have set up the Yahoo address in Outlook you can then change the settings so that you can send from the address we provide you. The following help sheet will show you how
Changing Your email reply address
We hope this is helpful.
Reason8 Support