Centos has by default installed python version 2.7.x, but CMSeeK will work only with python 3.6 (didnt tried another). Regerding this article https://linuxize.com/post/how-to-install-python-3-on-centos-7/ I set up temporary scl enable rh-python36 bash but this solution is just temporary. So I tried even make enviroment, but it works similar as scl enable...
So I tried add alias into .bashrc and this looks working: https://stackoverflow.com/questions/45542690/linux-centos-7-how-to-set-python3-5-2-as-default-python-version
nano .bashrc
add:
alias python3="/usr/bin/python3.4"
then logout / login from ssh.