# Troubleshooting overview

Source: https://developer.avalara.com/avatax-for-vat/htu7375612574214/

# Troubleshooting overview

Resolve common authentication problems quickly and effectively.

This section describes how to solve common problems associated with authentication.

Refer to the following troubleshooting topics for detailed solutions:

-   [Identify a firewall or proxy server problem](/avatax-for-vat/fys7292932125587/ "Learn how to identify and resolve connection issues caused by firewalls or proxy servers blocking AvaTax URLs.")
-   [Other common problems overview](/avatax-for-vat/yhi7523302416054/ "Learn how to address common authentication problems.")