Hi,
Thank you for you input.
Could not make it work with Postman, so I did some digging and found my problem.
<basicHttpBinding>
<!-- HTTPS and credentials enabled. -->
<binding name="Production">
<security mode="TransportWithMessageCredential">
<message clientCredentialType="UserName" />
</security>
</binding>
</basicHttpBinding>
Should be
<basicHttpBinding>
<!-- HTTPS and credentials enabled. -->
<binding name="Production">
<security mode="Transport">
<transport clientCredentialType="Basic" />
</security>
</binding>
</basicHttpBinding>
And now it works..