Interesting. webmail.syrahost.com is a branded RoundCube installation. We also used to use RoundCube, and have also seen that error message. But when we did, it was because the email storage server was down. If that’s the case too at Crazy Domains, that’s something they would need to fix.
Unless… their webmail server specifically tries to connect to the mail server at mail.rosesinhand.com to find the mail server. A quite unusual way to setup the webmail which makes things a bit harder.
So the key point I see there is that the mail server IP is 203.17087.185. They also say you should point mail.rosesinhand.com to it, but that’s hard because you can’t change the A records here.
Usually it’s possible to work around this by using the Reverse DNS record of the IP address. Just like a domain name points to an IP address, an IP address should also always point to a domain name. And then this domain name should point back at the IP address.
The reverse DNS of the IP points to mail.mywebstats.com.au, but that domain does not point back to any IP address. This means the workaround won’t work, but may also negatively affect email delivery, because correct IP configuration is one of the things spam filters tend to look at.
So I would urge Crazy Domains to setup a proper reverse and forward DNS pair for their mail servers.
You would order the hosting and email service at iFastNet and create the email accounts and forwarders there. Then, you change the MX records of your domain to point to iFastNet’s server, and then any new email would be delivered at iFastNet instead of Crazy Domains.
Finally, you may want to migrate your existing emails from the Crazy Domains mailbox to iFastNet. There are multiple ways to do this, but I just plug both accounts into Thunderbird and copy the messages from one account into the other from there.