Please Install the Updated Packages.
Mozilla Thunderbird is a standalone mail and newsgroup client. This erratum blacklists a small number of HTTPS certificates. (BZ#689430) This update also fixes the following bug: * The RHSA-2011:0312 and RHSA-2011:0311 updates introduced a regression, preventing some Java content and plug-ins written in Java from loading. With this update, the Java content and plug-ins work as expected. (BZ#683076) All Thunderbird users should upgrade to this updated package, which resolves these issues. All running instances of Thunderbird must be restarted for the update to take effect.
thunderbird on CentOS 4
Updated on 2015-03-25