Hi. Same issue. You say “check if you have enabled Authenticated SMTP for your Office 365 account”, but this is deprecated – Microsoft will allow some command line option to briefly turn it on, but ALL tenants will have the service completely disable dby September 2025 – see https://learn.microsoft.com/en-us/exchange/clients-and-mobile-in-exchange-online/deprecation-of-basic-authentication-exchange-online. Are you saying that your much-hyped “FluentSMTP” Microsoft integration was never deveopled to harness EWS or OAuth, and is dependant upon “SMTP AUTH” which is depracated?
