diff --git a/src/Feeds/Fetcher/Form/HttpFetcherFeedForm.php b/src/Feeds/Fetcher/Form/HttpFetcherFeedForm.php
index fde3ffd..ebaea17 100644
--- a/src/Feeds/Fetcher/Form/HttpFetcherFeedForm.php
+++ b/src/Feeds/Fetcher/Form/HttpFetcherFeedForm.php
@@ -62,7 +62,9 @@ class HttpFetcherFeedForm extends ExternalPluginFormBase implements ContainerInj
       $url = Feed::translateSchemes($form_state->getValue('source'));
     }
     catch (\InvalidArgumentException $e) {
-      $form_state->setError($form['source'], $this->t("The feed's scheme doesn't match a scheme recognized by this module. Accepted schemes are http, feed, webcal, https, feeds, and webcals."));
+      $form_state->setError($form['source'], $this->t("The url's scheme is not supported. Supported schemes are: @supported.", [
+        '@supported' => implode(', ', Feed::getSupportedSchemes()),
+      ]));
       // If the source doesn't have a valid scheme the rest of the validation
       // isn't helpful. Break out early.
       return;
diff --git a/src/Utility/Feed.php b/src/Utility/Feed.php
index 512f5d1..83006f9 100644
--- a/src/Utility/Feed.php
+++ b/src/Utility/Feed.php
@@ -124,4 +124,21 @@ class Feed {
     throw new \InvalidArgumentException();
   }
 
+  /**
+   * Returns which url schemes are supported by Feeds.
+   *
+   * @return array
+   *   The support schemes.
+   */
+  public static function getSupportedSchemes() {
+    return [
+      'http',
+      'feed',
+      'webcal',
+      'https',
+      'feeds',
+      'webcals',
+    ];
+  }
+
 }