This articles has been moved to its new home here: https://benperk.github.io/msdn/2012/2012-10-application-request-routing-arr-http-error-400-0-bad-request.html
I was working on setting up an ARR solution the other day and I ran into this error, and shown in Figure 1.
The request cannot be routed because it has reached the Max-Forwards limit. The server may be self-referencing itself in request routing topology.
Figure 1, HTTP Error 400.0 - Bad Request
The message pretty much explains the issue. I had added the server that was hosting my ARR instance to the list of servers that were going to manage the load. Figure 2 shows that on my server WIN-99*** where I had installed ARR, that I had included that same server in the Servers list.
Figure 2, ARR Servers list
I removed the WIN-99*** from the list and the request was routed to the other server. I later added additional servers to the Servers list so that the load is balanced across more than a single instance.