Post IDOC failed from ECC to SUS via PI...

Error log:
SM58 (in ECC) - EDISDEF: Port **** segment defn **** in IDoc type ****
SM21 (in PI) - Transaction Canceled IDOC_ADAPTER 155 ( "port" "segment" "parent segment" )

Root cause:
Inconsistency of IDOC metadata between ECC and PI.

Solution:

• Login into PI ABAP stack
• Open tcode IDX2
• Expand IDOC types and look for parent segment as shown in log (under SM21)
• Delete parent segment
• Execute messages in SM58 in ECC