Avalara Transport Layer Security Update To TLS 1.2

Avalara announced in this post an update in their REST v2 API security, that is the API used by the AvaTax connector for SAP Business One.

TLS (Transport Layer Security) protocol is used to access Avalara and consume the API for calculations. Avalara announced that using TLS version 1.2 or superior will be mandatory starting 2022, stopping support for older versions.

For Sandbox accounts since Feb 1, 2022.

For Production accounts since March 30, 2022.

The AvaTax solution: AvaTax Add-on, AvaTax EventService and AvaTax WebUI were updated since 2021 versions to use TLS 1.2 or superior.

If you have an Avatax connector with version 21.xx.xx or superior you don’t require any action.

If you are running versions prior to 21.xx.xx you must upgrade to a newer version.

If you want to confirm your installed version is supported:

  • Test AvaTax, using your assigned Sandbox Account and appropriate Sandbox URL starting 2/1/2022.
  • Once configured, attempt to do a tax calculation.
  • If your test system is successful at calculating tax, or test connection succeeds, then your environment is secure and no changes are needed.
  • If you receive a connection error, please upgrade your integration to the most current AvaTax Add-on.


In case your webUI instance is raising a connection error during connection test or calculations like this:

System.Net.WebException: The request was aborted: Could not create SSL/TLS secure channel.

This indicates your server is trying to connect to Avatax using TLS 1.0 or TLS 1.1, that is no longer supported by Avalara.

You must configure your webUI instance to use .Net Framework 4.6, that uses TLS 1.2 by default.

Edit your web.config file, located in avatax/api and add the following line, or edit it if already included in the file:

<httpRuntime targetFramework="4.6" maxRequestLength="56000" />