As you can see from the error message, it lists server outlook.office365.com. It reflects a Microsoft server that is used for Microsoft 365. A similar issue can happen with on-premises Exchange if WinRM is not configured properly. As such there is an issue with WinRM on the server and only Microsoft can fix it.
It is not necessary that all Adaxes customers will face the same issue because there are lots of Microsoft servers all around the globe and the issue can be only on some of them. It means that you will face the issue only if connected to the server which has the issue.
In Adaxes 2021.1, it is possible to specify the national cloud for your Microsoft 365 tenant. It changing the setting might help remedy the issue.