As we have mentioned before, duplicate accounts can create issues and you will see [pii_email_3ceeb7dd155a01a6455b] code. When you are signing in from a fake or duplicate account, Microsoft Outlook will show this code. In this case, you can fix this issue by removing that duplicate account. To remove a duplicate account, you have to implement this:
When you are using an old version of Microsoft Outlook, you might see the error code. This is why you should always update your PC and software. If you are finding the error code often, check if Microsoft Outlook is up to date or not. Then, update the software by using Wi-Fi.