diff --git a/Source/BluemixAppID/internal/TokenManager.swift b/Source/BluemixAppID/internal/TokenManager.swift
index 90fd13a..6e11962 100644
--- a/Source/BluemixAppID/internal/TokenManager.swift
+++ b/Source/BluemixAppID/internal/TokenManager.swift
@@ -114,7 +114,7 @@ internal class TokenManager {
                     return
                 }
                 
-                switch (response.statusCode) {
+                switch (response.statusCode ?? 500) {
                 case 400:
                     guard errorJson?["error"] == "invalid_grant", let errorDescription = errorJson?["error_description"] else {
                         fallthrough