IF ISA/IEA already exist in the edidata in TN then you dont need to use addICEnvelope explicitly…
Did you installed EDI document Types in TN thru WmEDI admin page??
Also make sure the doctypes X12Envelope,X12Group,X12 4010 810 (your transaction set) are enabled under TN DocumentType section.
Also if you are using TN TPA (Agreements) make sure your splitOption (Interchange or Group or Transaction) any of these in your default or partner specific TPA??
HTH,
RMG
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