Problem
When sending emails out using Thunderbird email client, customers are getting the following error. "your certificate contains the same serial number as another certificate issued by the certificate authority. Please get a new certificate containing a unique serial number"
Solution
To resolve this issue, you will need to delete a certificate for your outgoing mail server found within your thunderbird application.
Open Thunderbird then go to: Tools -> Options -> Privacy -> Security -> View Certificates -> Web Sites, then delete the certificate listed for your website/domain or the WESH server name. You may then need to close and reopen Thunderbird for this to work.
