It appears the LiquidFiles SMTP relay configuration does not work. Syslog has the following message: smtp.office365.com[52.96.180.114] said: 535 5.7.139 Authentication unsuccessful, basic authentication is disabled Are there plans to support modern authenitcaiton for Office 365 smtp relay in the future?
The SMTP basic authentication still should work in the 365 service and you should still be able to re-enable it in your 365 sending account. The termination of the SMTP basic authentication was postponed till first half of 2027 for tenants created prior December 2026. After then I would recommend to switch to a other party, less restrictive, SMTP relay service providers like smtp2go.com If you really can't switch from Ms 365 then it's possible to configure their ACS (Azure Communication Services) connector which will still support the SMTP basic authentication or finally remains the OAUTH2 method, which uses short-lived tokens instead of stored passwords, but it's not suitable for servers. But LF appliance supports that OAUTH2 authorization since v4.3 beta (v4.2.5x).
