When accessing the SEDR appliance pages (Dashboard, Search, Users) through the SEDR cloud console, you see the error "Cannot find user <SEDR cloud user> on the EDR appliance yet." when impersonating that customer account.
The Impersonate function in SEDR cloud does not enable you to access SEDR appliances integrated with the customer account you are impersonating. In order to see the SEDR appliance pages, you must be logged in to an account under the customer account where the appliance was registered.