Proxies just and getting error No implementing class

Question

Below are the steps I am seeing of a once functioning proxy any help will be greatly appreciated
When I send a test message from runtime workbench, it shows up in sxmb_moni as a green flag, clicking in the message I see the following error
<Trace level="1" type="B" name="CL_XMS_MAIN-WRITE_MESSAGE_TO_PERSIST" />
- <!--  ************************************
  -->
  <Trace level="1" type="T">--start sender interface action determination</Trace>
  <Trace level="1" type="T">select interface</Trace>
  <Trace level="1" type="T">select interface namespace</Trace>
  <Trace level="1" type="T">--start receiver interface action determination</Trace>
  <Trace level="1" type="T">Loop 0000000001</Trace>
  <Trace level="1" type="T">select interface SI_9002_SAP_FI_Send</Trace>
  <Trace level="1" type="T">select interface namespace http://sempra.com/sapfi/AccountingData</Trace>
  <Trace level="1" type="T">--no sender or receiver interface definition found</Trace>
  <Trace level="1" type="T">Hence set action to DEL</Trace>
  </SAP:Trace>
From SXMB_MONI I click into the queue and unlock to force a send, after doing that I recheck SXMB_MONI and the flag is red for failed with the following message
No implementing class registered for the interface
(ABAP interface, request message ..........)
I then check to ensure the proxies are still active along with the class and they are. I also ready about checking the rfc H connection via sm59 and doing the connection test I received a 500 empty HTTP Response which is good?
So my question, my proxies did work but all of the sudden are failing? Has anyone seen this issue before and if so any idea on how to fix it?
Cheers
Devlin

Answer 1

<Trace level="1" type="T">--no sender or receiver interface definition found</Trace>
<Trace level="1" type="T">Hence set action to DEL</Trace>
Check these:
Re: Moni Issue
no interface found
Regards,
Abhishek.