there are quite a few users who are experiencing problems upon their first frontend login, however, the login works the second time for most of them. The corresponding threads are at least these:
I believe that most of these issues occur for users visiting your page from a URL other than the livesite URL set in your global config. Lets imagine your livesite URL is http://www.example.com, but a user visits you under example.com. Indeed, there is no possibility for this user to login on the first attempt. Now, if you encounter such problems, you might be lucky, as some (if not all) these issues have been identified.
If you are willing to test this proposed solution, please follow these steps. But before you start, keep in mind that all such changes could as well break your site, so I wouldn't use it on a production system, but rather only on a test system.
- Use the attached files only on Joomla! 1.0.11. They are not compatible with other versions!
- Make a backup of the files /includes/joomla.php and /modules/mod_login.php first.
- Download the zip-file which is attached to this post, und unzip it to a temporary location.
- Overwrite /includes/joomla.php with joomla.php.
- Overwrite /modules/mod_login.php with mod_login.php.
- If you have set a value for the "Login Redirection URL" for the login module, please delete it or make sure the domain matches the domain you use as your live_site in global configuration.
- Please report back if you are still experiencing any login issues.
Looking forward to your feedback,