diff --git a/src/Eher/OAuth/OAuthServer.php b/src/Eher/OAuth/OAuthServer.php
index 55e7fc2..d0166c0 100644
--- a/src/Eher/OAuth/OAuthServer.php
+++ b/src/Eher/OAuth/OAuthServer.php
@@ -175,7 +175,7 @@ class OAuthServer {
       $request,
       $consumer,
       $token,
-      $signature
+      Util::urldecode_rfc3986($signature)
     );
 
     if (!$valid_sig) {