diff --git a/Reverse-Proxy-Diagnostics-Troubleshooting.md b/Reverse-Proxy-Diagnostics-Troubleshooting.md
index 1939866..f56fe7f 100644
--- a/Reverse-Proxy-Diagnostics-Troubleshooting.md
+++ b/Reverse-Proxy-Diagnostics-Troubleshooting.md
@@ -180,8 +180,16 @@ Last-Modified: Wed, 13 Mar 2024 05:36:47 GMT
 
 ## using ngrep
 
-One can use `ngrep` to watch traffic between reverse proxy and "radicale" (example) - but only senseful if this connection has no encryption active.
+One can use `ngrep` to watch traffic between reverse proxy and _radicale_ (example) - but only senseful if this connection has no encryption active.
 
 ```
 ngrep -d lo port 5232
-```
\ No newline at end of file
+```
+
+# Authorization Header suppressed
+
+## Apache + WSGI
+
+Required option to use user authentication of _radicale_: `WSGIPassAuthorization On`
+
+See also example configuration: https://github.com/Kozea/Radicale/blob/master/contrib/apache/radicale.conf
\ No newline at end of file