Thank you for posting this question in the support community forum. Unfortunately, we would need to know why the server is rejecting the request. Also, the ADTRAN's configuration would be helpful, but based on the debug, it appears to be working properly, but it isn't authenticated, but we are unable to determine why without seeing the debug on the server.
We have several guides on configuring AAA, 802.1x, Radius, and TACACS+. Here is the Configuring AAA in AOS guide. Here is the Configuring 802.1X in AOS guide. Here is the 802.1x Port Authentication and How It May Be Used in a Network guide. Here is the Configuring Microsoft IAS for Radius Authentication with AOS guide.
Please, do not hesitate to reply to this post with any additional information or questions. I will be happy to help in any way I can.