I have two services and am sending pretty chunky messages between them (~100kb). Though the previously mentioned value is typical of the size of the message, it is possible for
There are ocassional problems with WCF that will cause it to fail "silently" (i.e. no exception) which can be hard to debug. Sounds like this might be the case you're seeing.
In this case, enabling the tracing options in WCF can be extremely helpful, as it should allow you to see if the message is indeed reaching the service and how the dispatcher is dealing with it.