Why doesn't Django runserver start when importing postgresql_psycopg2?

Question

PostgreSQL

I am deploying a local project on Django 1.11.3
When runserver displays in the console:

Unhandled exception in thread
...
from psycopg2._psycopg import (  # noqa
ImportError: /home/***/py_prj/***/env/lib/python3.6/site-packages/psycopg2/.libs/libresolv-2-c4c53def.5.so: symbol __res_maybe_init version GLIBC_PRIVATE not defined in file libc.so.6 with link time reference

I work through virtualenv (in Python 3.6.5 virtual environment)
Googled the reason: stackoverflow
Installed and reinstalled the psycopg2 package for different versions of Python, updated pip, changed the version of Python in the virtual environment (like I tried everything that was offered on the stack) - the result is 0.
As fix the problem?
Well, just in case:
postgresql installed, database created, imported
Django 1.11.3
Ubuntu 18.04