diff --git a/CHANGELOG.md b/CHANGELOG.md
index d7cba34c..f6e2556b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -30,6 +30,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com), and this
 
 * [#507](https://github.com/shlinkio/shlink/issues/507) Fixed error with too long original URLs by increasing size to the maximum value (2048) based on [the standard](https://stackoverflow.com/a/417184).
 * [#502](https://github.com/shlinkio/shlink/issues/502) Fixed error when providing the port as part of the domain on short URLs.
+* [#509](https://github.com/shlinkio/shlink/issues/509) Fixed error when trying to generate a QR code for a short URL which uses a custom domain.
 
 
 ## 1.19.0 - 2019-10-05
diff --git a/module/Core/test/Action/QrCodeActionTest.php b/module/Core/test/Action/QrCodeActionTest.php
index b6cab5a7..ddb062dd 100644
--- a/module/Core/test/Action/QrCodeActionTest.php
+++ b/module/Core/test/Action/QrCodeActionTest.php
@@ -36,11 +36,11 @@ class QrCodeActionTest extends TestCase
     }
 
     /** @test */
-    public function aNotFoundShortCodeWillDelegateIntoNextMiddleware()
+    public function aNotFoundShortCodeWillDelegateIntoNextMiddleware(): void
     {
         $shortCode = 'abc123';
-        $this->urlShortener->shortCodeToUrl($shortCode)->willThrow(EntityDoesNotExistException::class)
-                                                       ->shouldBeCalledOnce();
+        $this->urlShortener->shortCodeToUrl($shortCode, '')->willThrow(EntityDoesNotExistException::class)
+                                                           ->shouldBeCalledOnce();
         $delegate = $this->prophesize(RequestHandlerInterface::class);
         $process = $delegate->handle(Argument::any())->willReturn(new Response());
 
@@ -50,11 +50,11 @@ class QrCodeActionTest extends TestCase
     }
 
     /** @test */
-    public function anInvalidShortCodeWillReturnNotFoundResponse()
+    public function anInvalidShortCodeWillReturnNotFoundResponse(): void
     {
         $shortCode = 'abc123';
-        $this->urlShortener->shortCodeToUrl($shortCode)->willThrow(InvalidShortCodeException::class)
-                                                       ->shouldBeCalledOnce();
+        $this->urlShortener->shortCodeToUrl($shortCode, '')->willThrow(InvalidShortCodeException::class)
+                                                           ->shouldBeCalledOnce();
         $delegate = $this->prophesize(RequestHandlerInterface::class);
         $process = $delegate->handle(Argument::any())->willReturn(new Response());
 
@@ -64,11 +64,11 @@ class QrCodeActionTest extends TestCase
     }
 
     /** @test */
-    public function aCorrectRequestReturnsTheQrCodeResponse()
+    public function aCorrectRequestReturnsTheQrCodeResponse(): void
     {
         $shortCode = 'abc123';
-        $this->urlShortener->shortCodeToUrl($shortCode)->willReturn(new ShortUrl(''))
-                                                       ->shouldBeCalledOnce();
+        $this->urlShortener->shortCodeToUrl($shortCode, '')->willReturn(new ShortUrl(''))
+                                                           ->shouldBeCalledOnce();
         $delegate = $this->prophesize(RequestHandlerInterface::class);
 
         $resp = $this->action->process(