One potential issue to watch out for when creating SIP credentials for an A2Billing customer is that the Account Code may not get set correctly if you do not choose the card number from the dropdown list, instead entering it manually.
For example, when you create a SIP account some fields are initially populated –
As you can see the Name and Account Code have been set the same. If you now know the card ID and enter that manually those settings will stay the same, with the incorrect Account Code.
However, if you click on the orange arrow and select the Card ID from the drop down list the ACCOUNTCODE gets set to the correct customers account code –