Hello!
Sorry that it happened to you. We are not sure what might have caused this bug.
Can you please try the next steps to see if the game works?
1. Close the game.
2. Go to the following folder and delete the "history" folder:
On macOS: ~/Library/Application Support/Lowpolis/x_purrsonline_x
On Windows: %userprofile%\AppData\LocalLow\LOWPOLIS\x_purrsonline_x
3. Launch the game again.