Not able to activate integration migrated to GEN3

Summary:

Hi all, I would thank any help with the following ( opened already an SR but no traction for now ).

I get error when activating integration in GEN3 after exporting in GEN2.

The integration is not very complex:

basically runs serveral REST apis in SaaS to update flexfield in ITEMS.

I get this error:

Last activation attempt failed.{0}. ; Failed to located the service endpoint for the service null. Please contact the administrator..
Integration VSD_INV_ITEMS_SET_EAN (1.0) cannot be activated.
{0}. ; Failed to located the service endpoint for the service null. Please contact the administrator..

How to fix

1. Verify and rectify the changes.