All solutions require you to have FTP access to your site either through a free program such as FileZilla, or your hosting control panel.
Regain Access to Your Admin
- Connect to your server via FTP go to wp-content/themes
- Rename your active theme’s folder to anything else. Example: store-off
- This requires at least one default theme in the themes folder, as WordPress will automatically attempt to activate TwentyFourteen
- Attempt to access your admin
- If this worked, reinstall the theme. See the following for detailed steps on doing this quickly and safely. How to reinstall your theme to fix fatal errors, unsynched updates or problems accessing your admin panel
- If this did not work, return to the FTP window and continue:
- Go to wp-content. Rename the plugins folder to plugins-off. This forces all plugins to deactivate.
- Attempt to access your admin.
- If this worked, you have a conflicting plugin. Proceed to activate and setup your theme without plugins activated, then reactivate them.
- If this did not work, resintall WordPress. See Unable to access admin or blank white page after install or update