A co-worker of mine came up with the solution.
Under the "HTTP Settings" section and in the "HTTP Content Type:" box entered: application/soap+xml
That solved the problem. The SOAP+XML monitor in SAM is now working without any issues.
not understand what you want
I came across this same situation and this helped, thanks!
Instead of " application/soap+xml", I had to replace the content type with text/xml;charset="utf-8""