I posted this already above and here the answer again. You may use any IP address of your server or any domain name that points to the IP of your server as imap server. So what does this mean? Your server has the IP 18.104.22.168, then use 22.214.171.124 as Imap server. Or your server has the hostname server.mydomain.com that exists in dns and points to the IP 126.96.36.199 then use server.mydomain.com as imap server. If you use a domain that does not exist it will not work of course as your imap client is not able to connect to a non existant domain.
And to your second error, you used the wrong login name. The login name for email accounts is the complete email address.