Hello, @moshe1111
Thank you for contacting us regarding your question!
You are absolutely right. Now we are checking the reason why this happens.
1. For translation you need to use the file with workpiece phrases of Membership plugin – membership-by-supsystic/app/lang/default.po
You can edit it using Poedit, a cross-platform gettext catalogs (.po files) editor.
2. Duplicate the default.po file and rename it to lang_COUNTRY.po
Example for the referenced plugin case: pt_BR.po
— pt_BR means Portuguese Brazil, but many languages don’t have a country variation…
— you’ll have to fill in with your own language
WPLANG in wp-config.php file must be set to your language, e.g., pt_BR
Every time you save in WordPress the .po file, PoEdit automatically generates a .mo file, which is the one WordPress uses and basically the only one you need to upload
3. Make the translation.
4. Create a directory supsystic-membership-lang in directory of your theme.
5. Add the translations (.po and .mo) files to this folder.
Or you can place your files by this path – /wp-content/languages/plugins/.
But in this case files should be name like this – membership-by-supsystic-pt_BR.po
Best regards,
Ole