We have seen reports of a malicious email that claims your mailbox is failing to sync and then providing a link to retrieve messages.
Do not click on this link. Do not provide information or follow links sent to you in emails, especially when they warn you of losing access to an account if you fail to do so. This is almost always a ploy from a malicious sender to get personal information or login credentials.
UofT in general and University of Toronto libraries in particular will not send links asking you to log into a site. You should always navigate to services using web addresses you know rather than ones provided in an email.