One of the errors stated: “com.sap.aii.af.service.administration.api.cpa.CPAChannelStoppedException: Channel stopped by administrative task”.
Whilst not completely obvious what the exact problem was, I check the CPA cache in transaction SXI_CACHE and ensured there were no errors during a full cache refresh.
No problems there.
So I moved on to check the communication channel itself. All seemed fine. Using the “check” option from the pull down menu, showed all was well.
No other errors.
Restarting the message from SXMB_MONI resulted in the same error over and over.
Simply editing the RFC communication channel in the Integration Directory and changing it to “Inactive”, saving and applying, then changing it back to “Active” (on the Advanced tab), saving and activating.
This seemed to fix the problem.
Looks like the RFC channel destination hostname was modified and this caused the adapter to throw a slight wobbler, making it think it was inactive.