Legacy authentication in Exchange Online uses a username and a password for client access requests. When legacy authentication is blocked for UTmail+ accounts, it can help to protect the University from brute force or password spray attacks and malicious connections that bypass our multi-factor authentication system.
With legacy authentication disabled, users with UTmail+ accounts must use email clients and apps that support modern authentication. These clients could include (but are not limited to):
Please update your email client to ensure that you are using the most recent version.
To learn more about common email clients and whether they support modern authentication, please review this knowledge base article on email clients that support modern authentication.