When connecting to an Exchange server using Outlook 2013 you may encounter an SSL trust error.
SSL trust error in Outlook 2013
The security certificate was issued by a company you have not chosen to trust. View the certificate to determine whether you want to trust the certifying authority.
If you choose Yes to proceed you may also encounter this additional error message.
Error: Outlook is unable to connect to the proxy server
There is a problem with the proxy server’s security certificate. The security certificate is not from a trusted certifying authority.
Outlook is unable to connect to the proxy server [servername] (Error Code 8).
This error occurs when the Exchange server is configured with a self-signed SSL certificate.
Outlook makes connections to the Exchange server over HTTPS and therefore must trust the SSL certificate that is configured on the server, otherwise it will display those error messages to the end user.
To resolve the issue install a valid SSL certificate on the Exchange server from a trusted certificate authority. See Exchange Server 2013 SSL certificates for more details on this as well as step by step instructions.
About Paul Cunningham
Ran into this last week. I don’t have a CA server in my Exchange 2013 lab so I put a copy of Exchange servers self signed cert into the clients trusted root store of the computer account to get past this.
well ,
is there any way to resolve issue without buying an external certificate from trusted certificate authorities?
for more than 3 years I am I have not faced this issue..
A certificate has to be trusted for it to be valid. If you don’t want to use a commercial CA then you can look into using a private CA instead.
However if you don’t already have a private CA in place then commercial CA’s are the best way to go.
well terms private and commercial should not be more confusing.
I have CA installed on Exchange server itself and has issued selfsigned certificate.
this set-up and certificate is working for other machines/clients. but not working for 2/3 clients.
what is Private CA ?
A private CA is one you install and maintain yourself in your environment, eg installing Certificate Services on a Windows Server in your Active Directory.
I don’t recommend installing Certificate Services on your Exchange server.
well that set-up there before I started managing it.
well any clue guess how I should take care of this issue