SYSTEM ERROR My Sql php registration form - php

Question

I've created a simple registration form for users to sign up to my website.
The first user went in fine, then I tried the second and I get an error when passing the information into the database. "Registration failed because of a system error:".
Here is the code that it's getting stuck on:
if (empty($errors)) {
$query = "INSERT INTO customers (first_name, last_name, email,
password) VALUES ('$firstname', '$lastname',
'$email', SHA1('$password'))";
$results = #mysqli_query ($conn, $query);
if ($results) {
echo '<h3>Thank you!</h3>
<p>You have successfully registered.</p>';
} else {
echo '<h3 class="error">System Error</h3>
<p class="error">Registration failed because of a system
error:</p>';
//DEBUGGING echo '<p class="error">' .
mysqli_error($conn) . '</p>
//DEBUGGING <p class="error">Query: ' . $query . '</p>';
}
mysqli_close($conn);
My form is:
<form action="signup.php" method="post">
<p>First Name: <input type="text" name="first_name" size="30"
maxlength="30" value="<?php if(isset($_POST['first_name']))
echo $_POST['first_name']; ?>" /></p>
<p>Last Name: <input type="text" name="last_name" size="50"
maxlength="50" value="<?php if (isset($_POST['last_name']))
echo $_POST['last_name']; ?>" /></p>
<p>Email Address: <input type="text" name="email" size="60"
maxlength="60" value="<?php if (isset($_POST['email']))
echo $_POST['email']; ?>" /> </p>
<p>Password: <input type="password" name="pass1" size="40"
maxlength="40" /></p>
<p>Confirm Password: <input type="password" name="pass2"
size="40" maxlength="40" /></p>
<p><input type="submit" name="submit" value="Register" /></p>
</form>
Why is the query not working? Why is the data not submitting into the database? My connection says to throw out an error if not database is not connected. As this error doesn't show up, I'm certain the connection is fine.
Edit: full php code..
<?php
if ($_SERVER["REQUEST_METHOD"] == "POST") {
require_once ('login.php');
$errors = array();
if (empty($_POST['first_name'])) {
$errors[] = 'You forgot to enter your first name.';
} else {
$firstname =
mysqli_real_escape_string($conn,trim($_POST['first_name']));
}
if (empty($_POST['last_name'])) {
$errors[] = 'You forgot to enter your last name.';
} else {
$lastname =
mysqli_real_escape_string($conn,trim($_POST['last_name']));
}
if (empty($_POST['email'])) {
$errors[] = 'You forgot to enter your email address.';
} else {
$email =
mysqli_real_escape_string($conn,trim($_POST['email']));
}
if (!empty($_POST['pass1'])) {
if ($_POST['pass1'] != $_POST['pass2']) {
$errors[] = 'Your passwords did not match.';
} else {
$password =
mysqli_real_escape_string($conn,trim($_POST['pass1']));
}
} else {
$errors[] = 'You forgot to enter your password.';
}
if (empty($errors)) {
$query = "INSERT INTO customers (first_name, last_name, email,
password) VALUES ('$firstname', '$lastname',
'$email', SHA1('$password'))";
$results = #mysqli_query ($conn, $query);
if ($results) {
echo '<h3>Thank you!</h3>
<p>You have successfully registered.</p>';
} else {
echo '<h3 class="error">System Error</h3>
<p class="error">Registration failed because of a system
error:</p>';
//DEBUGGING echo '<p class="error">' .
mysqli_error($conn) . '</p>
//DEBUGGING <p class="error">Query: ' . $query . '</p>';
}
mysqli_close($conn);
exit();
} else {
echo '<h3 class="error">Error</h3>
<p class="error">The following error(s) occurred:</p>';
foreach ($errors as $message) {
echo "<p class='error'>$message</p>";
}
echo '<p>Please try again.</p>';
}
mysqli_close($conn);
}
?>