Zend certified PHP/Magento developer

Data migration: missing configurable attributes after migration from 1.9.4.2

after completing a data-migration trying to exclude the import of products I can no longer complete the saving of a configurable product and the following window is shown
configurable modal

I have a dump of the db created before migrating (with all configurable products ok), which table can I look at to try to solve the problem? thank you all in advance