Now that we have discovered that the catch all Exception handler doesn't work, I've created a custom exception (SendNotificationQueueError) that handles this case and an error handler for it.

Talked these through with @becca as an approach.

app/errors.py

@@ -6,6 +6,7 @@ from sqlalchemy.exc import SQLAlchemyError, DataError
 from sqlalchemy.orm.exc import NoResultFound
 from marshmallow import ValidationError
 from app.authentication.auth import AuthError
+from app.notifications import SendNotificationToQueueError
 
 
 class InvalidRequest(Exception):
@@ -83,6 +84,11 @@ def register_errors(blueprint):
         current_app.logger.exception(e)
         return jsonify(result='error', message="No result found"), 404
 
+    @blueprint.errorhandler(SendNotificationToQueueError)
+    def failed_to_create_notification(e):
+        current_app.logger.exception(e)
+        return jsonify(result='error', message=e.message), 500
+
     @blueprint.errorhandler(SQLAlchemyError)
     def db_error(e):
         current_app.logger.exception(e)