This ancient post is 9 years old and gathering dust. It is probably not relevant anymore.
The original question was regarding a blank WordPress login page when trying to login to WordPress. After putting in your login information you are directed to a blank WordPress page instead of being logged into the WordPress Dashboard.
Before you start working via FTP to fix the WordPress blank login page problem try refreshing your browser at the blank page to see if the refresh gets you completely logged into your WordPress Dashboard. If you do get in then use the information below to start troubleshooting the cause. First thing to do is try clearing your cache and then see what happens after you log out and try to log back in to WordPress.
FYI – The default WordPress login script file is /wp-login.php so if you have a login plugin that you need to rename via FTP then you will have to login using the default WordPress login script.
There are 2 things that typically cause this WordPress blank login page problem in WordPress. The first thing to check is your wp-config.php file for any blank spaces after the very last line of code. You will need to FTP to your WordPress website since you cannot login. Download the wp-config.php file from whatever folder WordPress is installed in. wp-config.php is located in the root folder of a WordPress installation. Open the file in a website / web page editing program if you have one. If you don’t have a website editing program then you can open the wp-config.php file in WordPad or Notepad. Right mouse click and choose WordPad to open the file. Now take your mouse click on the last line of code after all code in the file and delete any white space after the last line of code. Upload the wp-config.php back to your WordPress website folder.
The WordPress blank login page is also commonly caused by a corrupt or malfunctioning plugin or a combination of caching and login plugins logically. Since you can’t login into your WordPress website you will have to fix the problem via FTP. In this particular case the problem that had occurred was that WP Cache plugin had become corrupted. Not only the cache itself, but actually the plugin itself. The user had performed an update to the Theme My Login plugin and had closed their WordPress website without trying to log out or test to see if everything was ok or clear their cache manually. Other plugins may cause this problem as well. For this solution I am only discussing how to correct this specific WordPress Blank Login page problem.
FTP to your WordPress website and renamed advanced-cache.php and wp-cache-config.php
This files are located in the /wp-content folder
See if you can login at this point. If you are still getting a blank login page try refreshing your browser. If you are still getting a blank login page then if you may have to rename the actual wp-cache folder under plugins. Also you may need to also rename other plugins that relate to logging in like the Theme My Login plugin.
Once you are logged backed into your WordPress website successfully you may be able to salvage the WP Cache plugin depending on how and where the corruption occured, but I think it is best the you do a clean install to ensure that you will not have any problems in the future. Especially if you see an error like this under the WP – Cache settings page after you have renamed your advanced-cache.php and wp-cache-config.php files and clicked out of the WP Cache settings page and back into settings.
Main options advanced-cache.php link does not exist
Create it by executing:
ln -s /home/content/XX/XXXXX/html/XXXXX.com/wp-content/plugins/wp-cache/wp-cache-phase1.php /home/content/XX/XXXXX/html/XXXXX.com/wp-content/advanced-cache.php in your server.
Related Links:
https://www.wpcity.com/cant-login-to-wordpress-admin/