Websphere-outlook-store (Kalisto)
In MS Office 365, BASIC authentication is now disabled in all tenants. Before December 31, 2022, you could enable BASIC authentication for IMAP, POP3, and SMTP protocols if users and applications in the tenant could not connect. Now, no one (neither you nor Microsoft Support) can re-enable BASIC authentication. Read the article Deprecation of Basic authentication in Exchange Online to fully understand the changes Microsoft has made and how these changes may affect you.