You are creating a Receivables Transaction Entry and it's not generating tax.
- Enable AvaTax integration for Receivables Transaction Entry in the Avalara configuration ("Tax Calculation" tab) in GP.
- On the Microsoft Dynamics GP menu, go to Tools > Setup > System > AvaTax, and then click Configuration.
- Next, close GP for the change to take effect.
- Ensure the "Tax Schedule ID" is set to "AVATAX"
- If still no tax, ensure Nexus is enabled for the state in the Admin Console
- Click the Address Id on the Receivables Transaction Entry in GP to see the state being used