Hi, the Workflow is working for me so if it doesn't work for you guys i guess it probably means the daily limit of the 'Synonyms account in the workflow' has been reached. I logged in, and it currently says "daily quota 895 out of 1000".
Anyway, you can solve this by applying for your own account here: http://www.synonyms.net/api.php
After registering you will get an email with an ID and Token, you need to enter them in the workflow here: