Support is available at AXLRadius.com.
Before contacting customer support please read the document RADIUS Trouble shooting which covers trouble shooting from the client side, but addresses most RADIUS protocol issues which are easy to check in the log files, particularly in the debug log file where packet contents are displayed. Often misconfigured NAS (Network Access Servers) and other clients are the problem. There may be issues running the RADIUS server.
Another avenue is to check the web site to be sure you have the latest version. The API documentation on the site also includes a change log under the link RADIUS Server Changes. Your problem may have been solved in a later version.
If you do find the problem requires support send the relevant logs (particularly the debug log) along with your description of the problem. The problem will generally be addressed within twenty-four hours. General RADIUS questions and software suggestions are also welcome and receive the same treatment.