If you're having a problem with the ApprovalMax-Dext-Xero connection, the reason could be that you're integrated directly with Xero.If this is the case, you need to change the integration in Dext.
This is how it works:
On the Integrations page in Dext, click on "Change":
Select "ApprovalMax for Xero":
If required, log into your ApprovalMax account and click on "Connect to ApprovalMax for Xero".
Select a valid Organisation with an active Xero connection and click "ALLOW ACCESS".
Once the connection has been established, all relevant Xero information will be synced to your Dext account, and you'll be able to select the respective values in the drop-down fields.