How to solve this issue?

"[email protected] [Abaqus]" <[email protected]> 25 Nov 2018 06:03:33 -0800

Newsgroups	gmane.comp.mathematics.abaqus.user
Message-ID	<[email protected]>

when I imported an implicit step into an explicit one the following msg reporting an error related to coupling constraint appeared:
 "SPECIFIED SURFACE ASSEMBLY_KM DOES NOT EXIST. THIS SURFACE MUST BE 
           DEFINED."
 knowing that I have redefined all BC's, interactions, constraints and loads.