Certificate authentication requires your Mac’s time to be in sync with the server your device is communicating with. So if the time on your Macintosh for some reason is off, then you may be getting these errors. Method 1 will help you check and potentially resolve this issue for you.
Method 1: Update/Check your date and time Mac OS X
Step 1: Click the Apple icon in the top right of your screen.
Step 2: Select the ”System Preferences” option out of the list provided.
Step 3: Set the ”Set date and time automatically” to a filled check box.
Wait a few moments and your OS X should update and clear you of certificate errors.
If it does not proceed to Method 2.
Method 2: Change trust settings for specific certificates
If this is the reason for it happening or it is only specific certifications. If you trust the service you’re connecting to, then you can modify the trust settings for the certificate to allow the authentication to proceed. To do this we need to open the Keychain Access utility.
Step 1: Use the ”command + space” to launch your computer’s internal search function.
Step 2: Type the following ”Keychain” and launch the Keychain Access application from the list below.
Step 3: You can search for the certification by looking up the domain name of the service in the search option provided inside Keychain access. (For example https://www.google.com, or Google.)
Step 4: If the certificate has a red ”X” symbol over its icon, then this means the certificate it has is expired or is otherwise invalid. In these cases, you can right-click the certificate and remove it from your system. When reconnecting to the site it will download the current certificate from the service again to authenticate.
If the certificate has a blue ”+” symbol, then this indicates custom trust settings have been applied to the certificate. This may be the reason for the issues you’re experiencing. For instance, a certificate may be used for SSL validation, but if the trust settings are not set up properly. Then OS X will prompt you to use this certificate every time an SSL connection attempts to use this certificate. Fixing this requires adjustment of the trust settings on the certificate. Below are the steps to resolve this.
Step 1: Double-click the certificate in Keychain Access to open it.
Step 2: Expand the ”Trust” settings
Step 3: Select ”Use System Defaults” from the top menu.
If you have any issues past this point or need additional help then consider HelpCloud Technician by-the-hour: