diff --git a/FAQ.md b/FAQ.md
index 07053a8..f83f1b0 100644
--- a/FAQ.md
+++ b/FAQ.md
@@ -1146,3 +1146,7 @@ When running in Windows Sandbox, it is not possible to obtain the user token fro
 > [2025-06-04 09:32:02.777040 +01:00] ERROR [src\platform\windows.rs:695] Failed to launch privileged process: The parameter is incorrect. (os error 87)
 >
 > [2025-06-04 09:32:02.777506 +01:00] ERROR [src\platform\windows.rs:700] No process winlogon.exe
+
+# Add root CA certificate into Docker container (for TLS failure with SMTP, OIDC etc.)
+
+https://github.com/rustdesk/rustdesk-server-pro/issues/99#issuecomment-2674522210