Language big problem - Very urgent request!

[StaruchM]

Very urgent request!

Welcome. I have a problem with the "Customer & Business Manager". In all possible settings, I have the Polish language. Translation does not work. Everywhere outside the main panel plesk is English. Please help urgently!

The main panel is working correctly the Polish language. I checked the file on the server is the language - Polish. What am I supposed to do?

greetings
Marcin Staruch