Add SSL instructions

Author: rasbt

ch02/01_main-chapter-code/ch02.ipynb

@@ -179,7 +179,36 @@
    "id": "56488f2c-a2b8-49f1-aaeb-461faad08dce",
    "metadata": {},
    "source": [
-    "- (If you encounter an `ssl.SSLCertVerificationError` when executing the previous code cell, it might be due to using an outdated Python version; you can find [more information here on GitHub](https://github.com/rasbt/LLMs-from-scratch/pull/403))"
+    "<br>\n",
+    "\n",
+    "---\n",
+    "\n",
+    "<br>\n",
+    "\n",
+    "#### Troubleshooting SSL certificate errors\n",
+    "\n",
+    "- Some readers reported seeing ssl.SSLCertVerificationError: `SSL: CERTIFICATE_VERIFY_FAILED` when running `urllib.request.urlretrieve` in VSCode or Jupyter. \n",
+    "- This usually means Python's certificate bundle is outdated.\n",
+    "\n",
+    "\n",
+    "**Fixes**\n",
+    "\n",
+    "- Use Python ≥ 3.9; you can check your Python version by executing the following code:\n",
+    "```python\n",
+    "import sys\n",
+    "print(sys.__version__)\n",
+    "```\n",
+    "- Upgrade the cert bundle:\n",
+    "  - pip: `pip install --upgrade certifi`\n",
+    "  - uv: `uv pip install --upgrade certifi`\n",
+    "- Restart the Jupyter kernel after upgrading.\n",
+    "- If you still encounter an `ssl.SSLCertVerificationError` when executing the previous code cell, please see the discussion at [more information here on GitHub](https://github.com/rasbt/LLMs-from-scratch/pull/403)\n",
+    "\n",
+    "<br>\n",
+    "\n",
+    "---\n",
+    "\n",
+    "<br>"
    ]
   },
   {