Basic/legacy authentication shows your username and password to an application when they try to login on your behalf to an application. Most comprised login attempts use basic authentication.
More securely, modern authentication sends a special code which avoids displaying your username and password to applications.
Email software that uses basic authentication are no longer available to access uOttawa emails. Only modern authentication will be permitted. Since the University’s emails are stored on Microsoft servers in the cloud, everyone needs to use email software that has modern authentication.