.de email can join but .com cant login

Hello Everyone,

I have recently registered a MS Teams workspace for my company we might switch from slack to ms teams. We use several email domains so for example mailto:name@company.de and mailto:name@company.com.

So far everyone using the .de email is able to join the platform without any issue. However people with mailto:name@company.com gets this error:

And some are not even able to go this far, they get the error that the email is not registered. So is there anyone who can help me with this?

I know that emptying the cache did help some the first time but I learned that it doesnt work for all people.

Thanks

Cheers,

Ashwin