Quite some time ago we enabled SSL support for email and webmail. This is a good thing as it dramatically improves security of your email and webmail access. Unfortunately this created a rather annoying problem with the security certificates. The security certificate was provided by the internet service provider and not us. As a result modern web browsers and email clients raise a warning message informing you that the certificate does not match the domain. This involved having to manually accept the certificate and is obviously a little off putting. In the last couple of months the cost of buying a security certificate has fallen massively and we will shortly implement a certificate for mtheory.co.uk. This should eliminate the warning messages raised by your email clients and web browsers.
However, when the switch happens (hopefully in the next week) your email client and web browser is likely to throw up a warning that the certificate has changed. You should be able to accept this and then things should work just fine from then on.
We will of course detail the transition here and if necessary add some support articles on the process.