Yahoo uses Java technology to display its elements, regarding e-mail and any other web based services. If you encounter a temporary error then you should visit the suggested links in order to restore the good functionality of the e-mail service.
On the other hand, your browser should meet the requirements and have e-mail or any other service displayed properly in other terms you should use Chrome, Firefox, Internet Explorer or any modern browser updated to its latest version.
Go to the Java download website and install the new package in case you have an obsolete version.
