Question

Error while External user is updating case
Hi,
I have a flow in which when External user is trying to update the case am getting below error:
"Error: You lack access required to execute RULE-OBJ-ACTIVITY CODE-PEGA-LIST PYGETALLATTACHMENTS #20140912T072640.850 GMT. "
Can anybody is aware of the cause of this issue.
Regards,
Prashant Nagargoje