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

I reported the "issue" to Mircosoft and had a 1 hour long session with 3 different support specialist with them on July 11. I showed them the exact probelm. There should even be a case number for the issue now, #7045845624.
Unfortunately, I did not get any update since then. I remember a similar issue about 8 to 9 years ago. After a few month it started working again. I am hoping this time it will be faster.
Best,
Dominik

I'm having the same problem.

Starting on or before July 17th, when I try to send from any of my aliases using Outlook.com, the Outlook New app, or the Outlook iOS app, the email won't send and gets stuck in the draft folder instead. In addition, when I try to send an email from an alias using the Outlook iOS app, the email shows in the sent folder but doesn't go through. Then, after I check my account using Outlook.com or the Outlook New app, when I go back to my Outlook iOS app, the email in my sent folder has disappeared. This happens across all devices and browsers.

Oddly enough, I'm able to send emails from aliases in the Classic Outlook app with no problem at all.

Update: I've been chatting with Microsoft support for 4+ hours and I've already chatted with 5 tech support reps and am waiting on a 6th. Microsoft doesn't seem to have a clue about this issue.

Yes I’m still waiting in the hopw it might be fixed Real poor show from Outlook.com

I also have the same problem, about 2 weeks ago it just stopped working for no reason.. I've been searching all over for a solution and thus far nothing...

I have about 5 aliases setup in my outlook.com account, from which I send mail ... I can receive mail from all of them, and send normally from all except for one, a gmail account... not sure if your aliases are "gmail accounts" or not, but mine is, so I suspected the problem was maybe there ...

I did the same of removing and re-adding the faulty alias, but didnt solve the problem. I also checked in my gmail account to make sure that Microsoft/outlook was granted access to Gmail, and all seems correct (microsoft has access to read, compose, send, and permanently delete all your email from gmail) ... but still it wont work.

when I send a test email from that alias (in outlook.com), it just stays in the drafts folder and doesn't get sent. When I do it form the outlook app, it is marked as sent, but doesn't really reach the recipient. and If i check back in outlook.com, it doesnt show in sent folder.
After a while I get an error in the draft mail saying "you dont have permission to perform this action". So I suspect it has to do with that..
I found this in google forums and I believe that might be the cause, but so far I havent been able to get hold of any customer support to help on the topic.

https://support.google.com/mail/answer/7126229?hl=en&sjid=2804372637536619706-EU" To keep your account more secure, Gmail no longer supports third-party apps or devices which require you to share your Google username and password. Sharing your account credentials with third-parties makes it easier for hackers to gain access to your account."

this is pretty frustrating, if anyone has an update / solution please post it!
thnx!

An update: After over 6 hours on chat and the phone with 8 different Microsoft reps, I was told that Outlook.com no longer supports adding and syncing outside accounts, which is why my emails using the aliases for those accounts were winding up in the Draft folder.

This means that you can no longer send emails using aliases from third party email accounts, at least according to the support rep who finally was able to help me. This also is true for the new Microsoft Outlook app, which is modeled after the Outlook.com interface.

You can, however, still add third party email accounts to the old Microsoft app for Windows as well as to the iPad/iPhone Microsoft app. To do so with the mobile app, I had to delete all email accounts, including my Outlook email account, re-add them, then restart the app. You may have to delete all the accounts in the Windows app as well. I’m not sure since I haven’t used the app in decades and only started again when the issues with aliases occurred a few weeks ago on Outlook.com.

As I mentioned, it took me over 6 hours and 8 different reps to get answers from Microsoft about these issues. The last rep actually called me so that he could more easily help me fix things, which I greatly appreciated. I have a Microsoft 365 subscription, which allegedly comes with “premium” support. Clearly, Microsoft’s definition of “premium” and mine are extremely different.