Problem with the sender address.
I usually use an alias to login and send mail with Outlook Web. With the classic version, when logged with my alias mail address, recipients see my emails sent from this alias mail address.
With the new version, they see my emails sent with my outlook address (outlook_F62xxxxxxxxx@outlook.com... This is very uncomfortable for my contact and they think that it is spam...
I think this should work as in the classic version.
For emails it seems to work for me, but I have this issue with calendar appointments which I am sending and my replies to calendar invites from others, those are sent with this wired outlook_G54xxxxx@outlook.com address. Why? Please use the standard sender defined in the settings. (or even better, allow me to chose which sender it takes each time)