diff --git a/PFERD/ilias_authenticators.py b/PFERD/ilias_authenticators.py
index 1924554..0336ac7 100644
--- a/PFERD/ilias_authenticators.py
+++ b/PFERD/ilias_authenticators.py
@@ -33,6 +33,7 @@ class ShibbolethAuthenticator:
         "text/xml",
         "text/xml;charset=UTF-8",
         "text/plain",
+        "text/plain;charset=UTF-8",
         "image/jpeg",
         "image/png",
     ]