Cannot Verify Server Identity
The identity of "server.flx.com.au" cannot be verified by Mail.
If you are able to accept this certificate, then this is safe to do so. Some phones do not allow you to accept the certificate, in which case you will need to make some changes.
To rectify this issue, you will need to change the incoming (and possibly outgoing) mail server settings from the server.flx.com.au to the one that matches your domain.
For example, if your domain is http://testnewdomain.com.au then change the incoming mail server to: mail.testnewdomain.com.au (substitute the testnewdomain.com.au portion with your domain name).
Sometimes your outgoing mailserver is set to your ISP server (such as mail.bigpond.com or smtp.bigpond.com) to enable you to send mail through their system. If this is the case, then you need to leave this set to the ISP setting. If your outgoing mailserver is set to server.flx.com.au, then you will need to change it to yours, i.e.: mail.testnewdomain.com.au.
If you are unable to edit settings
Some devices will not allow you to change the mailserver settings. If this is the case, you will need to set up a second email account on your device using the same login information and the new incoming/outgoing mailserver setting as described above. Once you have done this, verify that you can log in with the new email account and that all of the emails in your email account have downloaded.
Once you are happy this account is working, you may disable or delete the original email account.