MacOS Mail app "Unable to verify account name or password"

I have several emails within Hosted Exchange, every email worked fine with Mail app on MacOS - mail and calendar. Everything according to the guide of OVH. However couple of months ago these accounts stopped working and configuration of any of these Exchange accounts also become impossible. After entering the email and password there's a message "Unable to verify account name or password"

* Everything worked perfectly earlier so the problem is pretty unexpected
* This happens an different MacOS devices and Mail app versions. For example my machine hasMacOS 14.3.1 and Mail app version is 16.0.
* The same is for another account with same Hosted Exchange email for another domain
* Web version of email provided by OVH works fine
* Accounts error check procedure doesn't find anything
* Password change doesn't work
* Date/time of MacOS is set to automatic - I've seen that some people struggling with this problem fixed it by setting the automatic timezone.

OVH support says if web version works fine than it's technically not their business.

Appreciate any help