General developer forum

If users can't login then it means you aren't creating the users correctly. But you really shouldn't upload users through Phpmysql. Creating a user involves a lot more than just inserting their record into the mdl_user table.

It's much safer to create the users via a php page that uses the Moodle core API's to create the user profiles. Example: you could create a web service that uses user_create_user() to create the users, as explained in https://moodle.org/mod/forum/discuss.php?d=333851#p1345396 or https://moodle.org/mod/forum/discuss.php?d=326159#p1311484

I went down this road a long time ago and then decided it would be better to use the Moodle code to create users using user_create_user() function. 

One reason why pertains to the password which needs to be encoded. I would advise you look into calling the function update_internal_user_password() to set the password. You can pass a text password and it will encode it properly and store it in the database in the correct manner. If your case is such that the password you provide is only a temporary one and you want the user to change the password upon their first login, then you should make a call to set_user_preference() right after update_internal_user_password(). I will show you here what I mean:

        $user = new object();
        $user->password = "password"; // not sure but I think password cannot be blank, maybe I'm wrong, see below.. 
        $user->idnumber = $values["StudentID"];
        $user->firstname = $values["FirstName"];
        $user->lastname = $values["LastName"];
        $user->username = $values["Username"];
        $user->phone1 = $values["HomePhone"];
        $user->phone2 = $values["MobilePhone"];
        $user->email = $values["Email"];
        $user->mnethostid = 1;
        $user->confirmed = 1;
        $date = new DateTime($values["StartDate"]);
        $user->timecreated = strtotime(date('Y-m-d', $date->getTimestamp()));
        $new_userid = user_create_user($user, false, false); 
        $new_user = $DB->get_record('user', array('id'=>$new_userid));
        // set default password
        update_internal_user_password($new_user, 'password');
        // force password change
        set_user_preference('auth_forcepasswordchange', 1, $new_user);