diff --git a/app/Auth/Access/Guards/LdapSessionGuard.php b/app/Auth/Access/Guards/LdapSessionGuard.php
index 3c98140f6..84f54ad29 100644
--- a/app/Auth/Access/Guards/LdapSessionGuard.php
+++ b/app/Auth/Access/Guards/LdapSessionGuard.php
@@ -44,11 +44,14 @@ class LdapSessionGuard extends ExternalBaseSessionGuard
     public function validate(array $credentials = [])
     {
         $userDetails = $this->ldapService->getUserDetails($credentials['username']);
-        $this->lastAttempted = $this->provider->retrieveByCredentials([
-            'external_auth_id' => $userDetails['uid']
-        ]);
 
-        return $this->ldapService->validateUserCredentials($userDetails, $credentials['username'], $credentials['password']);
+        if (isset($userDetails['uid'])) {
+            $this->lastAttempted = $this->provider->retrieveByCredentials([
+                'external_auth_id' => $userDetails['uid']
+            ]);
+        }
+
+        return $this->ldapService->validateUserCredentials($userDetails, $credentials['password']);
     }
 
     /**
@@ -66,11 +69,15 @@ class LdapSessionGuard extends ExternalBaseSessionGuard
     {
         $username = $credentials['username'];
         $userDetails = $this->ldapService->getUserDetails($username);
-        $this->lastAttempted = $user = $this->provider->retrieveByCredentials([
-            'external_auth_id' => $userDetails['uid']
-        ]);
 
-        if (!$this->ldapService->validateUserCredentials($userDetails, $username, $credentials['password'])) {
+        $user = null;
+        if (isset($userDetails['uid'])) {
+            $this->lastAttempted = $user = $this->provider->retrieveByCredentials([
+                'external_auth_id' => $userDetails['uid']
+            ]);
+        }
+
+        if (!$this->ldapService->validateUserCredentials($userDetails, $credentials['password'])) {
             return false;
         }
 
diff --git a/app/Auth/Access/LdapService.php b/app/Auth/Access/LdapService.php
index 07e9f7b64..0d6ebfc80 100644
--- a/app/Auth/Access/LdapService.php
+++ b/app/Auth/Access/LdapService.php
@@ -102,9 +102,9 @@ class LdapService extends ExternalAuthService
      * Check if the given credentials are valid for the given user.
      * @throws LdapException
      */
-    public function validateUserCredentials(array $ldapUserDetails, string $username, string $password): bool
+    public function validateUserCredentials(?array $ldapUserDetails, string $password): bool
     {
-        if ($ldapUserDetails === null) {
+        if (is_null($ldapUserDetails)) {
             return false;
         }
 
diff --git a/tests/Auth/LdapTest.php b/tests/Auth/LdapTest.php
index cb1194e22..06f88c222 100644
--- a/tests/Auth/LdapTest.php
+++ b/tests/Auth/LdapTest.php
@@ -166,7 +166,7 @@ class LdapTest extends BrowserKitTest
             ->seeInDatabase('users', ['email' => $this->mockUser->email, 'email_confirmed' => false, 'external_auth_id' => 'cooluser456']);
     }
 
-    public function test_initial_incorrect_details()
+    public function test_initial_incorrect_credentials()
     {
         $this->mockLdap->shouldReceive('connect')->once()->andReturn($this->resourceId);
         $this->mockLdap->shouldReceive('setVersion')->once();
@@ -186,6 +186,23 @@ class LdapTest extends BrowserKitTest
             ->dontSeeInDatabase('users', ['external_auth_id' => $this->mockUser->name]);
     }
 
+    public function test_login_not_found_username()
+    {
+        $this->mockLdap->shouldReceive('connect')->once()->andReturn($this->resourceId);
+        $this->mockLdap->shouldReceive('setVersion')->once();
+        $this->mockLdap->shouldReceive('setOption')->times(1);
+        $this->mockLdap->shouldReceive('searchAndGetEntries')->times(1)
+            ->with($this->resourceId, config('services.ldap.base_dn'), \Mockery::type('string'), \Mockery::type('array'))
+            ->andReturn(['count' => 0]);
+        $this->mockLdap->shouldReceive('bind')->times(1)->andReturn(true, false);
+        $this->mockEscapes(1);
+
+        $this->mockUserLogin()
+            ->seePageIs('/login')->see('These credentials do not match our records.')
+            ->dontSeeInDatabase('users', ['external_auth_id' => $this->mockUser->name]);
+    }
+
+
     public function test_create_user_form()
     {
         $this->asAdmin()->visit('/settings/users/create')