Getting error as failed to execute /bin/bash : Permission denied for ssh and su commands.

Issue

• While trying to putty or ssh from terminal to non-root users, getting error below and ssh session gets terminated.

  $ ssh -vvv username@server-ip
  /bin/bash : Permission denied
  

• For su to non-root user, getting similar errors

  # su - username
  Failed to execute /bin/bash : Permission denied
  

• The /var/log/secure file shows connection closed by user.