In order to fully understand what caused this failure, we will probably need to look at the equipment directly. I have generated a support ticket for you so that we can gather more information, and will send you a private message with further details. Once we have gotten to the root of the issue, we can come back to update this post. Thank you in advance.
I went ahead and marked this post Assumed Answered, because you were able to get some information from Adtran Technical Support. If there is any additional information feel free to add it in replies. Thank you.