Related item DFF context will show all the different relationship type DFF context(s). The correct value to select for GTIN DFF context code has the prefix ‘GTIN’. If you select any other value, the integrator will error. See here for more explanation on this limitation.
This is more4apps architecture limitation. This will be addressed in a future release.
GTIN
GTIN must be unique. You cannot update the ‘GTIN’ field to another GTIN. Unfortunately, the message returned from the integrator regarding the update is not very clear.
If you receive this message, it is referring to the fact that you cannot update the ‘GTIN’ field.