I am using a Post Form to add products and it works fine, except for a missing translation for "This field is required". At some form fields the German translation from the messages settings is visible. At others it simply isn´t; there´s still the English message.
I am not sure, how to use the gettext hook. I had a look at the related ticket and added the following to the functions.php with a snippets plugin. But that did not help:
Can you please share problem URL and admin access details and let me check what's going wrong with your setup.
*** Please make a FULL BACKUP of your database and website.***
I would also eventually need to request temporary access (WP-Admin and FTP) to your site. Preferably to a test site where the problem has been replicated if possible in order to be of better help and check if some configurations might need to be changed.
I have set the next reply to private which means only you and I have access to it.