Hi all. Can you please tell me why users keep getting the certificate popup even after we install the certificate on the computer. This is only affecting Outlook users It would appear that the certificate has a problem with it We click View Certificate, and then install the certificate successfully. After we click Yes we get another popup which asks for our password to logon to CAS Server These pop-ups happen 5 to 10 times a day so are very annoying.

Hi, You said it prompted a window about certificate, whats the exact error? Certificate is not trusted or something else? Do you use a self-signed certificate? Have you tried OWA? Does that prompt certificate window? Please choose both Basic authentication and NTLM authentication as your RPC virtual directory authentication method in IIS manager. Information collection: Run Test E-mail AutoConfiguration a. Launch affect users mail profile b. Hold Ctrl and click Outlook icon in the right-below corner of desktop tray c. Click Test E-mail AutoConfiguration d. Enter username and password e. Check Autodiscover, clear other selections and test f. Post the result here for our further discussion. Please run cmdlet get-exchangecertificate |fl on your CAS server and paste the result here. Thanks, Elvis

Dear Elvis Thank you for your reply and the error message is as follows: Security Alert autodiscover.kcompany.com Information you exchange with this site cannot be viewed or changed by others, However, there is a problem with the site's secutiry certificate. O The security certificates is from a trusted certifying authority. O The security certificate date is valid X The name on the security certificate is invalid or does not match the name of the site We have merged two company(K and D), so we use two seperated active directory server. They are seperated forest and non- trusted domain. The exchange mail server joined one company's(K) directory server(Kcompany.com). But D company's employees windows are joined D company's directory server(Dcompany.com). so only the other company's(D) employees get the security alert. K company's employee's are not required cetification when they turn on outlook client. I don't know why D company's employee are required certification. Regards Juhan

Hi Juhan, Im not clear how your configure your server. If Kcompany and Dcompany are separated forest and non- trusted domain. How users in Dcompany visit mailbox in Kcompany domain? You can run Exchange BPA to do a health check and then send the report to me. I await your reply, Elvis