On October 1, 2022, Microsoft will end support for Basic Authentication; that is, transmission of the username and password combination on all Microsoft APIs, in order to improve security across their product APIs.
Going forward, you can either set up your own SMTP Server for sending emails with eNotify or you can use a free SMTP server.
Free SMTP Servers
For a rundown of free SMTP Servers and how to choose the best one for your company, see this article, Free SMTP Servers for Sending Emails – 2022.