diff --git a/oidc_provider/lib/utils/common.py b/oidc_provider/lib/utils/common.py
index 6b625e3..236c12a 100644
--- a/oidc_provider/lib/utils/common.py
+++ b/oidc_provider/lib/utils/common.py
@@ -42,7 +42,7 @@ def get_issuer(site_url=None, request=None):
         .split('/.well-known/openid-configuration')[0]
     issuer = site_url + path
 
-    return issuer
+    return str(issuer)
 
 
 def default_userinfo(claims, user):