Server license check failed: _cffi_backend.cpython-36m-x86_64-linux-gnu.so: invalid ELF header

Issue

During the license check or activation, OpenSSL related error can be seen:

# rhn_check
Traceback (most recent call last):
File "/usr/sbin/rhn_check", line 44, in <module>
import OpenSSL
[...]
File "/usr/lib64/python3.6/site-packages/cryptography/hazmat/bindings/openssl/binding.py", line 16, in <module>
from cryptography.hazmat.bindings._openssl import ffi, lib
ImportError: /usr/lib64/python3.6/site-packages/_cffi_backend.cpython-36m-x86_64-linux-gnu.so: invalid ELF header

# /usr/sbin/rhnreg_ks --activationkey=<key>
Traceback (most recent call last):
[...]
from cryptography.hazmat.bindings._openssl import ffi, lib
ImportError: /usr/lib64/python3.6/site-packages/_cffi_backend.cpython-36m-x86_64-linux-gnu.so: invalid ELF header

Environment

• rhn_check
• Licensing

Solution

1. Reinstall the following packages:

   yum reinstall python3-pyOpenSSL python3-cffi
   

2. Check the license and/or re-register server:

   https://docs.cloudlinux.com/shared/cloudlinux_installation/#license-activation

Cause

Corrupted files