I have set up the Customer Feedback (Satisfaction check).
It states (here https://support.zendesk.com/hc/en-us/articles/203662256-Using-CSAT) that when we make the ticket 'solved' the user gets a message on his email after 24 hours to share his feedback. That does not work. Our tester did not get an email after 24h.

Hey Aleksandra,
Can you confirm you have the CSAT automation set up as mentioned in this article? Why are my satisfaction surveys not being sent?
You can find your automations under Admin>Business Rules>Automations.
Hope this helps!