Hello Oliver,
Did you import the Encryption module beforehand?
If so can you open it in eclipse and verify which java file is failing the validation?
Hi Oliver,
I would check out the email module with templates. This is the one I normally use.
https://appstore.home.mendix.com/link/app/259/Mendix/E-mail-module-with-templates
Here is a blog post that explains how to set it up.
https://austinmcnicholas.com/blog/2019/2/24/setup-email-in-a-mendix-app-in-10-minutes-or-less-9ya8n
Hope this helps!