Outlook cannot access Teams (TeamsAddin is present and successfully installed)

I want to use Teams within Outlook. So I want to add a Teams-Link in new appointments.

My Environment:

• Windows 10 Pro
• Microsoft 365 Subscripton (Familiy).
• Microsoft Teams (Version: 24243.1309.3132.617. Indicated as most recent version of MS Teams)

What I already tried

• I am currently successfully logged into my Microsoft Account.
• I ran the Office Update to make sure every Office components are up to date
• I deinstalled and downloaded most recent version of MS TEams and installed it successfully

What is the problem? In Outlook I checked: File -> Options -> Calendar and found there is not Online Meeting Provider available:

 The selected account email address removed for privacy reasons is the correct Office 365 Account which is successfully setup (and displayed as MS Exchange Account)

I checked the Teams Addin under Com-Addins with Files->Options->Addins:

Now I see this 

"Anmelden" means login in English.

But when I click on the button the MS Teams Windows pops to front but nothing more happens. So the question is: Is there some functionality (like in my office that I can directly add a Teams Link to an appointment)

And still the online meeting provider dialog still shows no entries: 

Perhaps it's not possible to use Teams with Outlook from a Office 365 (Family) account? Can I find any info on this anywhere?