I can't get my emails

- What is your operating system? - What anti-virus, network security, or VPN programs do you use, if any? Certificate errors usually indicate a server problem. They are probably aware of it and are working on it. There's nothing you can do about it except to confirm your server settings, which can be found on their support web site. It might be helpful to contact them to report the problem and perhaps get a status report. Similar error messages can also be a result of local antivirus programs that can intercept your email connection and disrupt certificate verification. If so, you may be able to create an exception in the AV for Thunderbird.