diff --git a/webrtc.html b/webrtc.html
index 1c496646e..d7d30aca5 100644
--- a/webrtc.html
+++ b/webrtc.html
@@ -3154,8 +3154,10 @@ <h4>
                   If <var>parsedURL</var>'s' [=url/scheme=] is <code>"turn"</code> or
                   <code>"turns"</code>, and either of
                   <var>server</var>.{{RTCIceServer/username}} or
-                  <var>server</var>.{{RTCIceServer/credential}} do
-                  [=map/exist|not exist=], then [= exception/throw =] an
+                  <var>server</var>.{{RTCIceServer/credential}} are
+                  [=map/exist|missing=] or their UTF-8 representations
+                  fail to conform to [[RFC8489]] section 14.3 and [[RFC8265]]
+                  section 4.1 respectively, then [= exception/throw =] an
                   {{InvalidAccessError}}.
                 </p>
               </li>