bluehost ssl not trusted

Hello I just recently purchased a new SSL certificate for our domain from bluehost. Now I get the following error message from Thunderbird. Configuration not trusted. We received the configuration for your email over a connection that isn't as secure as we'd like. This means there is a tiny chance that someone could have altered it. Double check provided configuration. I entered my server dashboard and compared the manual email settings and the settings match exactly. I have paused anti-virus software on both my mobile and laptop and have uninstalled and reinstalled Thunderbird but nothing helped. Contacted Bluehost all is working fine. I can access my email from other clients but not from Thunderbird. Any thoughts thanks Gary K.