This issue is specific for Beeline Kazakhstan. I guess the problem is just like Artem said that there is Beeline Russia which is the ONLY Russian mobile operator to actually work with Digits.
In Kazakhstan, it's the ONLY Kazakhstani mobile operator which actually does NOT work with Digits.
There is a mistake in country-code for Kazakhstan.
For Kazakhstan, the country-code is +77.
For Russia, the country-code is +7, (all, except +77).