Cannot type in disk encryption password at boot

Hello,
I installed Kali Persistence with encryption on USB some few weeks ago.

I am on using Fujitsu E734 and when I want to boot Kali it gets to the screen when my disk password is required. But it will not let me put the password in. The built in keyboard is completely unresponsive. The input prompt just keeps blinking, but no action on keyboard is registered. I get stuck there for a long time, no progress. I do not have an external keyboard to test it there, anyway that would be quite impractical too...

I tested it on two computers before, everything went well, no problems.
When I chose to boot without encryption everything works (no password prompt) - I am writing this post booted like that right now.

Do you happen to know what the problem could be and how I could fix it, please?

Thank you very much for your advice and support.