Workflow - Sending email with "Send to contacts in a cell" isn't working

Hi!

I'm trying to set up a workflow which sends notifications only to a contact in a cell which is part of a contact column. 

Although permissions are set to "Unrestricted" the workflow isn't working!

A test environment with my name in the contact cell isn't working too.

Any idea what to check or change?

Thx in advance!