Error1: Not able to post idoc from sap ecc to sap pi ( AAE, single stack) , due to http connection is not valid.
error: when opening as RFC : connection
SAP -> SAP PI ( single stack connection) for idoc outbound.
Search results of google for this error as follows
verify the rfc destination (t type) program id ( Which is from ecc) in SAP PI NWA
use the same program id in same location.
Error2: we are not able send idoc from sap pi to sap ecc system, idoc is in waiting state,
reason: sap pi basis, modified the roles for this user(for SAP ECC system), after provide full roles , we were able to connect the system again.
simply re-sending the failed messages in sap pi monitor page.