diff --git a/commerce_coordinator/apps/lms/tasks.py b/commerce_coordinator/apps/lms/tasks.py
index f5e3c893..2bf22688 100644
--- a/commerce_coordinator/apps/lms/tasks.py
+++ b/commerce_coordinator/apps/lms/tasks.py
@@ -36,7 +36,7 @@ def on_failure(self, exc, task_id, args, kwargs, einfo):
         error_message = (
             json.loads(exc.response.text).get('message', '')
             if hasattr(exc, 'response') and exc.response is not None
-            else exc
+            else str(exc)
         )
 
         logger.error(
diff --git a/commerce_coordinator/apps/lms/tests/test_tasks.py b/commerce_coordinator/apps/lms/tests/test_tasks.py
index 5d312dfb..5a0df4de 100644
--- a/commerce_coordinator/apps/lms/tests/test_tasks.py
+++ b/commerce_coordinator/apps/lms/tests/test_tasks.py
@@ -3,7 +3,7 @@
 """
 
 import logging
-from unittest.mock import patch, sentinel, Mock
+from unittest.mock import Mock, patch, sentinel
 
 from django.test import TestCase
 from requests import RequestException
diff --git a/docs/conf.py b/docs/conf.py
index e1f70b19..7ff2388e 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -557,6 +557,8 @@ def setup(app):
     event = 'builder-inited'
     app.connect(event, on_init)
 
+# celery.Task has some roles inside the library that are not recognized by Sphinx
+# and causing errors, so we add them here to avoid the errors.
 rst_prolog = """
 .. role:: setting
 .. role:: sig