diff --git a/src/utility/url.cpp b/src/utility/url.cpp
index b8182427..d3c5445d 100644
--- a/src/utility/url.cpp
+++ b/src/utility/url.cpp
@@ -149,7 +149,7 @@ const string url::build() const
 
 			oss << urlUtils::encode(prop->getName());
 			oss << "=";
-			oss << urlUtils::encode(prop->getValue());
+			oss << urlUtils::encode(prop->getValue <string>());
 		}
 	}