I referred two people, but got an error that the invitation was invalid

[casatik]

Please help me with a technical issue.
I invited two friends to use Dropbox but got a notification that the invitation was invalid. The first person is my colleague, we work in the same office.
The other person is my daughter. We live in the same apartment. With both guests, we often use the same network to access the Internet. Maybe that's why the invitation looks suspicious? Could you help me solve this problem?
It is very convenient to share documents with both your daughter and a colleague through the Dropbox shared folder. I would also like them to get a little bonus of 500MB of extra storage.

I appreciate your help and look forward to any suggestions in this regard.

[Hannah]

Hey @casatik, welcome to the Dropbox Community.

Can I actually send you an email, so we can look into this internally?

Let me know!

[casatik]

Of course. I am waiting for your letter.

P.S. I apologize for the delay in reply. I'm from Ukraine, it's not always possible 

[personal info removed, per the Dropbox Community Guidelines]

[Jay]

Hi @casatik, I've sent you an email, please could you reply to it as soon as possible to look into this further?

[casatik]

Hello, Jay. 

I replied to your email.

[Jay · Accepted solution]

Thanks, I've replied to your email just now. Feel free to reply when you get a chance.