Problem with Teams

[SteveBatty375]

The situation:

I subscribe to Microsoft 365 home.
I have a business email address and own the domain. This is hosted by a third party - not Microsoft.
Approx. 4 weeks back I was able to access TEAMS as a GUEST of numerous organisations. I noted I also had a Work or school account in the Windows settings, Accounts, Emails and accounts.

Approx 4 weeks ago guest access to Teams stopped for all organisations (the organisations have checked that everything is set correctly at their end) and I no longer have any work or school account.

How can I revert back to the functionality provided 4 weeks ago?

[#2]

Can you still login and use Teams? What yso you mean you no longer have an account?

[#3]

@adam deltinger 

No I can no longer login and use Teams with any of the guest accounts. I can get into Teams but that is it.

Sometime if these organisations ask me to join a call I cannot use Teams as it asks for a user name NOR does it give me the option to use the browser. Hence I cannot join the call (unless I use a phone which defeats the object of Teams).

I no longer have an account. 
In the Windows10 settings, under the Accounts and then Emails and Accounts there is an option to add a work or school account. I used to have my business email address listed as a work or school account. This is no longer there. And I cannot add a work or school account.

I hope this provides greater clarity