Our Miva account got updated last week causing us to spend some time and several calls to Miva before things were resolved. We added a new Miva user name specifically for SEOM order retrieval use that does not require any special authentication. Miva support had to set this up.
After we creating the new user in Miva, go to "Setup Wizard" in SEOM, select "Shopping Carts" then "Create and Edit Shopping Carts", select the Miva cart if you have multiple carts listed, click "Edit", enter the new User Name and Password, save then click the Test Script URL to make sure the new user / pw work properly. Save and exit the Setup Wizard.
Hope this helps,
Bob R
CycleBuy.com
using SEOM since 2008. Still on 5.938 Enterprise. Happy to see SEOM coming back to life ...