diff --git a/.github/.lychee.toml b/.github/.lychee.toml
index 65a9d7ff..afba9909 100644
--- a/.github/.lychee.toml
+++ b/.github/.lychee.toml
@@ -37,7 +37,9 @@ exclude = [
   "https://docs.ray.io/.*",
   "https://awslabs.github.io/palace/.*",
   # PyPI file downloads in uv.lock return transient 503s
-  "https://files.pythonhosted.org/.*"
+  "https://files.pythonhosted.org/.*",
+  # refractiveindex.info returns 404 transiently
+  "https://refractiveindex.info/.*"
 ]
 # Exclude paths that contain template variables or are known false positives
 exclude_path = [
diff --git a/notebooks/sax_01_sax.ipynb b/notebooks/sax_01_sax.ipynb
index d40cbaa2..2123b7e2 100644
--- a/notebooks/sax_01_sax.ipynb
+++ b/notebooks/sax_01_sax.ipynb
@@ -7,7 +7,7 @@
    "source": [
     "# SAX circuit simulator\n",
     "\n",
-    "[SAX](https://flaport.github.io/sax/) is a circuit solver written in JAX, writing your component models in SAX enables you not only to get the function values but the gradients, this is useful for circuit optimization.\n",
+    "[SAX](https://gdsfactory.github.io/sax/) is a circuit solver written in JAX, writing your component models in SAX enables you not only to get the function values but the gradients, this is useful for circuit optimization.\n",
     "\n",
     "This tutorial has been adapted from the SAX Quick Start and example notebooks.\n",
     "\n",