Django 4.0 added a RedisCache which we moved to when upgrading to Django 4. Previously we were using django-redis. This is causing 500 errors to be returned when the redis connection fails.

django-redis had a IGNORE_EXCEPTIONS setting that we used. It's possible that redis was always having connectivity issues in ephemeral and it now only visible because we are no longer ignoring these exceptions.

To unblock the Django 4 release, we are moing back to using django-redis.