diff --git a/Auth0/SafariWebAuth.swift b/Auth0/SafariWebAuth.swift
index dcb99363..904e9cc6 100644
--- a/Auth0/SafariWebAuth.swift
+++ b/Auth0/SafariWebAuth.swift
@@ -211,7 +211,7 @@ class SafariWebAuth: WebAuth {
             let returnTo = URLQueryItem(name: "returnTo", value: self.redirectURL?.absoluteString)
             let clientId = URLQueryItem(name: "client_id", value: self.clientId)
             var components = URLComponents(url: logoutURL, resolvingAgainstBaseURL: true)
-            components?.queryItems = [returnTo, clientId]
+            components?.queryItems?.append(contentsOf: [returnTo, clientId])
             guard let clearSessionURL = components?.url, let redirectURL = returnTo.value else {
                 return callback(false)
             }