This is because your yahoo account requires captcha code during login.
WMN could handle captcha input in older version of yahoo mail login page.
Recently yahoo changed this to complicated AJAX style page.
For WMN cannot handle it, just open new tab instead of captcha dialog.
If you see login screen, login manually and click 'Check Now' in WMN.
If you don't want to see new tab
Options -> Select your yahoo account -> Uncheck 'Show login verification window'
This is because your yahoo
This is because your yahoo account requires captcha code during login.
WMN could handle captcha input in older version of yahoo mail login page.
Recently yahoo changed this to complicated AJAX style page.
For WMN cannot handle it, just open new tab instead of captcha dialog.
If you see login screen, login manually and click 'Check Now' in WMN.
If you don't want to see new tab
Options -> Select your yahoo account -> Uncheck 'Show login verification window'
That seems like that worked
That seems like that worked but now its not checking to see if I have any new emails.
You can enter captcha code
You can enter captcha code in dialog as before in WMN 2.9.1
http://webmailnotifier.mozdev.org/installation.html