Carry out the procedure Pairing a Hideez Key device with Windows 10 and Creating a PIN code on a Hideez Key device for FIDO technology
Follow Dropbox setup instructions How to use a security key for two-step verification
On the authorization page, enter your username and password in the usual way.
On-screen you will see a request for checking if you have a security key - if Hideez Key is enabled, then nothing needs to be done. If it is not on, turn it on with a short press.
Enter the PIN code created earlier here.
Queries are coming to your security key.
And a screen appears asking you to take action on the security key.
Press the button. At this time, the button flashes green.
You are authorized in your Dropbox account!