Just a hunch. Try disabling the ZoneAlarm Toolbar extension and see if you can send an email thru Yahoo.

Problem happens only on yahoo mail (I'm on PC). It's not only when clicking for sending mail on yahoo's website as Anonymous says. It's all buttons that are in yahoo mail. But bizarrely, you can right click on buttons and open in new tab and it will load. I don't use ZA. I installed recently Trusteer, but it's inactive now... I should try to uninstall it maybe. All other websites are functional and ok.

I have a Mac and also cannot send or forward emails in yahoo mail. Error message states "Message could not be sent due to connection problem." Also having problems with online purchases, when attempting to submit an order I get variety of error messages of why my order can't process.

I get a "error 999" when trying to connect with yahoo mail. I've run every cleaner I have and still have now found a solution...Don't have zone alarm. Have installed nothing new since the last time I logged on

I don't have ZoneAlarm or the tool bar. My antivirus is McAffee through my internet provider. Called Yahoo and my tech support...nothing is working. I don't like to use IE...too slow. Any other ideas?

I also have this problem. Started after I removed duplicate Java applications from my PC. I am currently running Java 6, Update 26 (build 1.6.0_26-b03).

I have uninstalled and reinstalled Firefox 4.0.1.

Yahoo! email had worked until I did the Java cleanup. Works without any problem in Internet Explorer, but I prefer Firefox (if it works...).

My yahoo email works fine on my desktop but send and forward are missing when using my laptop. Browser = Firefox 5 email account yahoo.com