This error indicates that the ''[[:cmd:iseq]]'' command has compared two strings and found them to be not equal.

When using the ''[[:cmd:iseq]]'' command, you should always use the ''||'' operator to handle the case when the two strings are not equal.  For example:

    iseq ${answer} Y && goto is_correct ||

On Centos7 try disabling the firewall: systemctl stop firewalld.service