License active, but getting "Username and password do not match" error when creating a page

I have an active Gridbox license. I recently reinstalled my Joomla website and did a fresh installation of the Gridbox component.

In the Joomla control panel, under the "About Gridbox" section, I successfully logged in, and the system shows that my license is Active.

However, when I try to create a new page, a login prompt appears. After entering my login and password, I receive the following error message:

"Error: Username and password do not match or you do not have an account yet."

Could you please advise on how to fix this issue so I can start creating pages?

Thank you in advance for your help!