My yahoo mail always pop up a window mail undefined?-Collection of common programming errors

Make sure you login to Yahoo Mail using the correct address. Enter the correct address while sending any mail. Where exactly are you getting the error? While logging to your mail or after logging? Are you getting the error while downloading mails to a mail client? Try different browsers like Firefox, Chrome and Opera. I’m sure you’ll be able to get to your mail page using these any of these browsers. I recently switched to Chrome and it works well. Just make sure you download and use the updated versions. (Older versions are buggy and are prone to crashes)

?NOTE:-It has been said that Yahoo is doing some upgrading work and maintenance regularly and some users are still experiencing problems. So if you are not able to access your Mails, then try via this link (http://us.m.yahoo.com/p/mail ).It works!

NOTE: In case the above solutions didn’t work, you need to directly contact the Yahoo Customer Help Service for possible fixes for your problem. Use this link for more info on any topic about Y!mail (http://help.yahoo.com/l/us/yahoo/mail/ya. ).Good Luck