Receiving email on alias but not able to send any emails - Outlook on the web?

Ok, there is another "workaround":

You can create a new alias that is a e.g. "@outlook.com" email address. That email, ending with "@outlook.com" can still be used as alias and send emails.

That will not solve the problem of existing external email addresses, but it is a small step towards a potential solution (until hopefully Microsoft revokes its decision and enables all aliases again)

Well, if this is really no longer possible and will not be fixed I need to change my email as well. After ... 25+ years? That would be terrible. I am really hoping Microsoft reconsiders this decision.

Some here too. My main alias has always worked. It stopped working last week from one day to the other. The mails get stuck in the drafts folder, stay there forever and are never sent out.

Removing and re-creating my main alias doesn't help at all.

Then I created a test alias and interestingly that works fine. The only difference I see between the two alias' is, my main alias was previously a connected account until Microsoft stopped the connected account feature and converted the mail adress into an alias.

I tried it with Outlook New and Outlook Web - I have no 365 subscription.

Same issue for me. "Send from alias" turned is on in Exchange but no "Addresses to send from" section in Outlook. Every email sent just resorts to my primary.

Go to the top left side and click view on the right side of home. The addresses to send from will show on that setting option only. I dont know why these people dont explain that. I have enabled that so it shows im responding as my alias on my end (looks like it came to my primary until i go to reply then i see the alias email selected to reply) but on my tester email after I sent it from my alias to the person contacting me on the other end (that persons side-- sorry its hard to explain but i am using my personal email trying to test my primary and alias emails for work) it shows my primary email.