thanks Marvin
i look into files you referred to, but i didn’t find any entry about missing libraries…
Than i tried do export the workflow, delete the one i had, and import again…
Now it’s working fine
I don’t know if the export/import process was the solution or I’m just lucky,
Anyway…everything seems fine now…
I wait few days before closing post, just in case the error should rise up again.
Thanks anyway for the answer.
Alessandro