I can't log into the Joomla! backend as administrator

There are a few common issues that could be causing the problem. The solutions below may help you regain access to your Joomla! administrative backend.

• Change the password of your administrator user

If you receive Username/Password authentication errors when you attempt to log in to the administrative area of your website (e.g. http://yourdomain.com/administrator) you should change the password of your Joomla! admin user.

You can do that from phpMyAdmin as shown here.

• The account for your user is blocked

Any user can be blocked from Joomla!’s backend – additionally, a user can be blocked if he had too many failed login attempts. Once that user is blocked, he won’t be able to log in (even if the password is correct).

You can unblock your user via phpMyAdmin, by going to the users table (e.g jom_users – the table prefix jom_ may be different, depending on your Joomla! setup), and then set the block field for the affected user to 0 (instead of 1).

• Seeing a blank page instead of the login screen

There might be multiple causes to this problem and most of them are related to PHP incompatibility issues between one (or multiple) of the core Joomla! files that load the login screen. You can change the PHP version of your website using PHP Manager in Site Tools and verify if the administrator page is loading.

• Getting a JAuthentication error message

If you are receiving the following error message when you enter your login details:

JAuthentication::__construct: Could not load authentication libraries.
Username and password do not match

Most probably the problem is caused by disabled Authentication – Joomla! plugin.

First, access your phpMyAdmin in Site Tools and select your database from the left menu. If you don’t know exactly which database is used by your Joomla!, check this article. After that, you should see all tables of your database, listed on the left side.

Select the plugins table (e.g jom_plugins). Find the record named Authentication – Joomla! and press the Edit button (pencil icon) for that entry. You should see all preferences for this plugin, find the row called “published” and change its value from 0 to 1. Click on GO.

Access your admin area with your login details and verify if the issue persists.

• Check if the plugin User – Joomla! Is properly enabled

Go to your Site Tools > Site > MySQL and navigate to phpMyAdmin, select your database from the left menu, click on the plugins table (e.g jom_plugins), and select the User – Joomla! entry.

Make sure that the value next to the “published” field is set to 1. If it is different – this is the reason for the problem and you should change the value to 1. Click on GO and test if you can log in.