I don’t see the reason why someone would want to use multiple languages in one post. The international forum is largely in English (except for the section I mentioned), and the Russian forum is exclusively in Russian. But of course, you are welcome to ask the same questions here in English, and at the Russian forum in Russian, if you think you’d get a reply sooner that way. Both forums usually have people (developers included) who are able and willing to help.
I don't see the reason why someone would want to use multiple languages in one post. The international forum is largely in English (except for the section I mentioned), and the Russian forum is exclusively in Russian. But of course, you are welcome to ask the same questions here in English, and at the Russian forum in Russian, if you think you'd get a reply sooner that way. Both forums usually have people (developers included) who are able and willing to help.
I can assume that somewhere (for example in 3rd party addon) you have the following code
ini_set('display_errors', true);
If you have SSH access, perform search over all CS-Cart files by "display_errors"
Hello, thank you for your support. We did a check on all the files and fixed to not appear, but still the errors show. Can see after adding to cart if the user is not logged in, show error https://rio001.com/ru/cart/