VERIFIED SOLUTION i

MailStream Plus will not allow Standard Mail - Machinable Parcel. (ML TYP S M)

MailStream Plus™, all versions, all platforms

Issue

When setting a Standard Mail - Machinable Parcel-
ML TYP S M
*...+....1

MailStream Plus™ errors on the M

Cause

That is not an option, only Package Services mail can be Machinable Parcels.  So you cannot have ML TYP with an S (Standard Mail) in position 8, and an M (Machinable Parcel) in position 10.

Resolution

UPDATED: May 16, 2019
Determine the correct ML TYP settings that should be used for the mailing/mailpieces