We have a client running Exchange 2010 on a Windows 2012 R2 server with Outlook 2010/2013 clients. It has a UCC certificate from Godaddy! Everything has been fine with this server for months. A week ago the clients started getting certificate errors. The name on the security certificate is invalid or doesn't match the name on the certificate. Here is where it gets weird. The server name listed at the top of the security alert is mail.domainname.com.com ( Notice the extra .com). If you view the certificate it says issued to *.com.com by RapidSSL SHA256 CA - G3. One of my coworkers and I have been over this server and client pc's backwards and forwards and can not find where this certificate is coming from. Other than doing windows updates a couple of weeks ago nothing has changed on this server. HAs anyone got any ideas? The users can click yes to continue but they are getting annoyed with that. I've checked all the DNS entries at Network Solutions and on the local DNS and everything appears fine. I've done the Microsoft Exchange Connectivity tests and everything come back fine. Help Please.