This account is not supported in Outlook for Windows due to the license provided by your work or school

People, you are wasting your time.

Microsoft have you by the short and curlys and they know it.

Subscription price of business basic went from £3.80 (GBP) to £4.50 then to £4.90. now they are forcing 12 month contract unless you pay another 20% making it £5.88. same percentage increases on other packages. If you are a partner (reseller, even just a small indirect reseller) then they come after you if your client goes bump. The partner is on the hook for paying out the rest of the contract.

At the same time, they are forcing you to have licenses that you don't want, as in this very discussion here, and also in the case of office apps (word/excel) being signed-in to a secondary account that has business basic - accessing files on OneDrive for example. They are forcing you to pay for the full license for every single account even if all on the same computer and the same person, and at these massively inflated prices.

And the problem is.. there is no negotiation. You have no voice at all. It's take it or leave it. Google aren't any better really.

It's time to ditch them altogether. Go back to basics. IMAP mail or SoGo or something, libre office, back up your data with Kopia and Backblaze instead of OneDrive. Just say NO.

Well said Carl, 100% spot on.
I have a dozen customers who would run away from Microsoft if they could break the chains.

MicroShaft think they are like the government and us peasants have to tithe to rent our 2 acres of land.

The irony is the products are getting worse and worse with each iteration.

Tried the "new New NEW Outlook" OMG what an ABOMINATION, an entire department needs sacking for ever thinking this was a viable product.

But I've been in this game long enough to see giants fall, remember IBM, DIGITAL, Honeywell, Alta Vista, Jeeves, Lotus, etc.

I had the same issue like many others. I have switched back to the old version of Mail on my Windows and it works again, allowing multiple accounts (company and gmail accounts).

Will switch back to the new outlook only when this problem will be fixed by MICROSOFT.. no one is upgrading licenses for just having visibility on already purchased for accounts!! If by they time I will be "forced" to switch to the new outlook, the problem will still be there, I will "bye bye" outlook and move to google business. Up to you MS..

My work email works with Windows Mail desktop app, but not the new Outlook desktop app. So I won't be using the new Outlook until that issue is fixed.

Everyone in this thread is making excellent points. Just remember: Microsoft will not see them here. They are not looking here.

May I please beg each of you who have posted comments here to copy/paste them into the feedback portal here:

https://feedbackportal.microsoft.com/feedback/idea/2f7925cb-3a80-ee11-a81c-000d3ae46fcb

That is the place that Microsoft is watching. That is the place your comments need to be posted. The more activity we get there, the faster we can get this addressed. PLEASE consider taking a moment to paste your detailed comments in there! You will be helping yourselves, and everyone, to fix this huge issue.

Also please be sure to upvote it. The only way we can get ahead of this issue is to get this escalated through the system. Thank you!

FWIW, I just got confirmation from Microsoft Support that they are not permitting cheaper paid email accounts on new Outlook. No reason was given. My colleagues and I have put in a feedback request here: https://feedbackportal.microsoft.com/feedback/idea/2f7925cb-3a80-ee11-a81c-000d3ae46fcb  - anyone encountering this problem should consider upvoting that item.