diff --git a/handlers/util.go b/handlers/util.go
index 27c2d9f..d7e6dd5 100644
--- a/handlers/util.go
+++ b/handlers/util.go
@@ -18,7 +18,7 @@ func updateEndpointValidator(
 	// Check BasicAuth credentials
 	username, password, ok := r.BasicAuth()
 	if !ok || !util.CheckCredentials(authDB, validCredentials, username, password) {
-		w.Header()["WWW-Authenticate"] = []string{"Basic realm=\"spaceapid\""}
+		w.Header().Set("WWW-Authenticate", "Basic realm=\"spaceapid\"")
 		http.Error(w, "", http.StatusUnauthorized)
 		return []byte{}, errors.New(fmt.Sprintf("Unauthorized request from %s Username: %s Password: %s", r.RemoteAddr, username, password))
 	}