diff --git a/src/mod_matrix_gw.erl b/src/mod_matrix_gw.erl
index baafd64dc..5f9705422 100644
--- a/src/mod_matrix_gw.erl
+++ b/src/mod_matrix_gw.erl
@@ -744,6 +744,8 @@ is_canonical_json(B) when is_binary(B) ->
     true;
 is_canonical_json(B) when is_boolean(B) ->
     true;
+is_canonical_json(null) ->
+    true;
 is_canonical_json(Map) when is_map(Map) ->
     maps:fold(
       fun(_K, V, true) ->