SAP PO 7.5 Alerts problem with Office365

Hello everyone,

I’m facing a problem with the alert configuration in a SAP Process Orchestration 7.5 with an Office365 mail server.

I followed Michal’s blog http://scn.sap.com/community/pi-and-soa-middleware/blog/2012/03/25/michals-pi-tips-component-based-message-alerting and everything is working fine but sometimes (most of the times) the server is returning the following error:

But other times the alert is working fine and reaching mi inbox correctly:

This is are my Java Mail Client properties:

What is really strange is that with the same configuration sometimes it works and sometimes not. Has anybody faced this issue? Do you know how to solve it?

Thanks in advance,

Aketza.