Feb 18, 2022 · Sometimes, when a patient tries to sign in to the Patient Portal, they may get an error like this-This is because the patient may not have entered their first name, last name or date of birth exactly as how is it entered in CareStack. For example, if a patient's first name contains two parts in CareStack, say ' Test 123', the patient would have to enter ' Test 123' in the First ….