Firewall block & data transmitted over https

For a start I would follow the recommendation from the error message: “Please enable cookies”.
If you do not like to use cookies and if this is about the browser then open up a private/incognito window and accept all cookies. Once you close that window they will be gone again.

“Bitwarden is a Zero Knowledge/Zero Trust solution. This means that the team at Bitwarden, as well as Bitwarden systems themselves, have no knowledge of, way to retrieve, or way to reset your Master Password.”

Source: Your Master Password | Bitwarden Help & Support

And for some more details see here: