Are you using Latest version of Wordpress 5.1 and Email Customizer versions below 1.5.8 ?
Issue: While trying to Save the templates. Templates are not saving after editing the customized email templates.
Cause: This is a Known issue occurred with the latest version of Wordpress 5.1.
Make sure, you are updated Email Customizer plugin to the latest version (version 1.5.8). Here is guide to update the plugin -> How To Update Email Customizer . We have added the compatibility to the Wordpress latest version.
Even after updating the plugin if the Save is not working, kindly check if you have any security plugins on your site.
Templates are saving but, it sends the default woocommerce emails instead of the customized emails.
Check if you have enabled the templates from our plugin settings - Here is a guide on the same Enable/Disable Templates
If you are using WPML in your site, have a check on the default locale settings for each languages :
Wpml -> Site languages -> Edit language -> default locale.
Default locale: This determines the locale value for this language. You should check the name of WordPress localisation file to set this correctly.
Still Unclear ?
Send us a support request -> [email protected]