Thank you for asking this question in the support community. The definition of firewall messages can be found in the Configuring the Firewall (IPv4) AOS document. The information regarding this message from that document can be found below:
Description: Indicates that the fragments necessary to complete reassembly have not arrived in a timely manner. An attacker could have attempted to consume all of the resources in the reassembly engine of a server or other network device.
Action: The reassembly engine drops the offending fragments and frees the resource.
I hope that makes sense, but let me know if you have any additional questions or information. I will be happy to help in any way I can.
I went ahead and flagged this post as “Assumed Answered.” If any of the responses on this thread assisted you, please mark them as either Correct or Helpful answers with the applicable buttons. This will make them visible and help other members of the community find solutions more easily. If you still need assistance, I would be more than happy to continue working with you on this - just let me know in a reply.
Great! This is very helpful!