Hello there,
I understand from your message that your MailPoet is only producing English text output, even though German is set as the default language and the appropriate po file is installed in the plugin.
Can you confirm if the english text is displaying for all MailPoet pages? Is this affecting other plugins on your website as well?
Let’s try a few things:
Check the language setup: Please ensure that both WordPress and the MailPoet plugin are set to German. Also, confirm the .po file for the German language is located in the appropriate language folder ( of your MailPoet plugin. Ref: https://kb.mailpoet.com/article/169-translations-in-the-plugin
Please note?that translations added to?/wp-content/languages/plugins?will be used instead of the translations included with the plugin.
Clear Cache: Please clear the cache of your site and the browser history, and then check on different browsers or devices to see if the issue persists.
I hope this helps.
Cheers!