The Dutch translation isn’t finished. There is a partial translation within the plugin.
If you can do the translation that would be great!
There is a free program you can download that opens the translation file and then you can translate and save. It’s from https://poedit.net/
You need to open the file wp-content/plugins/church-admin/languages/church-admin-nl_NL.po to edit. I advise you to save it somewhere else while working on it. As it gets overwritten when you update the plugin! It would be awful to loose your work if you update, before it has been added in to installs for everyone!
When you have finished email it to me at support AT churchadminplugin.com and I will add it to the updates.
Thanks