Certificate errors

[me@lespearson.co.uk]

Some of my members are wishing to use webmail to access their email. However when I enter the site I get a security certificate error. I have tried adding 3 w's. to the URL but get the same. Is there anything I can do to fix this?
Whilst it does not bother me (i use outlook) it will my members.

Thanks in advance.

[DanL@Spry]

Have you opened a support ticket for this issue?