I see.
Have you just started playing Siberia Card? Did it not happen in the past?
I think something is corrupted.
You can try either of these solutions:
1) Close Firefox and restart. That may be enough. Browsers are sensitive things.
2) Oopen a training game of Siberia Card, then press Ctrl-F5 to force a reload, clearing the cache in the process. Your first game food will be lost.
3) if this did not work, then type about:preferences#privacy in the address bar, then:
3a) in the History section, click on the links that are in the sentence: You may want to clear your recent history, or remove individual cookies.
3b) click on the button "Clear now" in the Cached web content section
If it still does not help, try with another browser.
Try 1) first, then let us know if it worked. In case it comes back for another game/user, we'll have the solution ready.
Then 2), etc.