How to fix Opencart translation error after migration?

Question

opencart

After site transfer, instead of texts that are taken from the translation file, for example "Add to cart", "button_cart" (array keys in translation) is displayed on the entire site. What could be the problem?
I checked the paths, the rights on the folder with translations are 755, on files 644.

Answer 1

This problem occurs when the key is not found in the language file.
Check:
1. That the language code and the folder match
2. That the required file is in place
3. The required file contains a line with the required key
4. Check for modifications of the language files and the first 3 items for modified files