Today morning when i tried to login in my wp admin panel i faced a strange problem.
The wp-admin page was vanished like a blank page in wp-admin dir after than i tried to login via wp-login.php then i got an error says
“ERROR: Cookies are blocked due to unexpected output. For help, please see this documentation or try the support forums.”
But there where no Cookies blocked so i goggled my problem and found some useful answers like :
Reason Behind it:
One of the active plugins (or the theme’s functions.php file) produces unexpected output, causing a “headers already sent” warning and consequently preventing WordPress from setting the test cookie.
UTF-8 byte order mark in wp-config.php (or theme’s functions.php file) has the same effect as above.
In case of a plugin issue, the solution would be to rename its folder via FTP. In case of a UTF-8 byte order mark issue, the solution is to re-save the file without it. Notepad++ has an option for that: “Convert to UTF-8 without BOM”.
But both the solution doesn’t worked for me, then i checked my theme’s function.php and found that some extra code has been added to it so i just replaced it with the original function.php file and my problem was solved!
I also found that this error may be a Bug in WordPress 3.9, many user doesn’t get the genuine solution for there question, So you may ask here. May be i can help you