Hi Pieter try to map the Attribute to the %token% in the bottom of the same page
After that in the microflow call the java action “ReplaceEmailTemplateTokens”
Hope that helps!
Are you using the AppstoreApp “Email module with templates”? If so, in the microflow you should not fill the tokens, but the entities' attributes. The EmailTemplate app will take care of replacing the Template’s tokens with the attribute’s values, if you correctly defined the placeholders.
After the Java action do you commit the changed values? And try to test the mail functionality locally first with a tool like this one: https://github.com/rnwood/smtp4dev