send by category not working

Hello,

I need to send newsletters in different languages. I am using two different mailing lists (German contacts & Italian contacts) for this.
In order to filter my recent posts I tried to use categories and tags for the different Languages. Both times it did not work. Mail Poet seems not to read my “German” categories and tags.
(I am using WPML to manage the languages on my site.)

Any advice?
Thank You,
Laura

https://wordpress.org/plugins/wysija-newsletters/