diff --git a/Source/assets/html/loginregister.twig b/Source/assets/html/loginregister.twig
index b53129a..416b182 100644
--- a/Source/assets/html/loginregister.twig
+++ b/Source/assets/html/loginregister.twig
@@ -8,10 +8,14 @@
         </div>
         <div class="row">
             <div class="col-sm-12">
-            {% if page.state == 1 %}
+            {% if page.state == 'BAD_CREDENTIAL' %}
                 <p class="text-danger">Bad credentials</p>
-            {% elseif page.state == 2 %}
+            {% elseif page.state == 'POST_ERROR' %}
                 <p class="text-danger">Error during sign-up, check your data</p>
+            {% elseif page.state == 'MAIL_IN_USE' %}
+                <p class="text-danger">The e-mail is currently in use</p>
+            {% elseif page.state == 'NICK_IN_USE' %}
+                <p class="text-danger">The nickname is currently in use</p>
             {% endif %}
             </div>
         </div>
diff --git a/Source/src/DB.php b/Source/src/DB.php
index bab7326..ea3d17c 100644
--- a/Source/src/DB.php
+++ b/Source/src/DB.php
@@ -382,9 +382,9 @@ class DB
      * @param $email user's email
      * @return int user's identifier
      */
-    public function loadIDU($email)
+    public function loadIDU($field,$mode='email')
     {
-        $query = "SELECT IDU FROM Users WHERE email='" . $email . "'";
+        $query = "SELECT IDU FROM Users WHERE $mode='" . $field . "'";
         return $this->getQuery($query)["IDU"];
     }
 
@@ -434,7 +434,9 @@ class DB
     public function register($email, $pass, $nick)
     {
         if ($this->loadIDU($email))
-            return false;
+            return 'MAIL_IN_USE';
+        else if ($this->loadIDU($nick,'nick'))
+            return 'NICK_IN_USE';
         else {
             $password = hash('sha256', $pass);
             dbw_query($this->conn, "INSERT INTO Users (`email`,`pass`,`nick`) VALUES ('$email','$password','$nick')");
diff --git a/Source/src/app.php b/Source/src/app.php
index c42dfa0..213e9d8 100644
--- a/Source/src/app.php
+++ b/Source/src/app.php
@@ -162,7 +162,7 @@ $app->get('/signup', function(Request $request) use ($app){
 
 })->bind('register')->method('GET|POST');
 
-function loginRegister($default,$state=0){
+function loginRegister($default,$state=''){
     global $app;
 
     $page = array(
@@ -179,20 +179,21 @@ function loginOrRegister($state,$request){
 
     switch ($state){
         case 3:
-            return loginRegister('login',1);
+            return loginRegister('login','BAD_CREDENTIAL');
         case 1:
-            if(checklogin($request->get('email'),$request->get('pwd'))){
+            if(checklogin($request->get('email'),$request->get('pwd'))==''){
                 return $app->redirect($app["url_generator"]->generate('home'));
             }else{
-                return loginRegister("login",1);
+                return loginRegister("login",'BAD_CREDENTIAL');
             }
         case 2:
-            if(register($request->get('emailre'),$request->get('emailre-re'),
-            $request->get('pwdre'),  $request->get('pwdre-re'),$request->get('nick'))){
+            $state = register($request->get('emailre'),$request->get('emailre-re'),
+            $request->get('pwdre'),  $request->get('pwdre-re'),$request->get('nick'));
+            if ($state == '') 
                 return $app->redirect($app["url_generator"]->generate('home'));    
-            }else{
-                return loginRegister("sing-up",2);
-            }
+            else
+                return loginRegister("sing-up",$state);
+            
     }
 }
 
diff --git a/Source/src/users.php b/Source/src/users.php
index 24169d8..31dcbde 100644
--- a/Source/src/users.php
+++ b/Source/src/users.php
@@ -34,7 +34,7 @@ function checklogin($email,$pass){
         $_SESSION['token'] = $token;
         $_SESSION['sessionID'] =$idu;
         $db->close();
-        return true;
+        return '';
     }
     $db->close();
     return false;
@@ -51,14 +51,14 @@ function checklogin($email,$pass){
 function register($email,$emailre,$pass,$passre,$nick){
     $db = new DB();
     if($emailre != $email || $pass != $passre)
-        return false;
-    $bool = $db->register($email,$pass,$nick);
-    if($bool) {
+        return 'POST_ERROR';
+    $state = $db->register($email,$pass,$nick);
+    if($state) {
         $db->close();
         return checklogin($email, $pass);
     }else {
         $db->close();
-        return false;
+        return $state;
     }
 
 }