However, nothing is added to the database when I send test emails to the address. Is there any way to debug or test this and see where the issue is? This should trigger every time an email is received, no?
Ways to debug would be check the logs to see what values were passed to the field (likely will be empty so not helpful to understand how to fix, but helpful to understand the extraction is not correct)
To figure out what is wrong with extraction:
Create test page
Add the text from an example email
Apply the extraction to that text
Continue to tweak extraction until it works as required