Make sure that you're using the latest version and update Cerebro if necessary. You can download the latest version for your OS here: https://cerebrohq.com/en/download/.
Try resetting configuration files to default settings according to the steps below:
Go to the directory containing Cerebro configuration files.
For Windows: Using Explorer, go to the %APPDATA% directory (you can enter the name into the Explorer search field and press Enter).
For Linux: Open the File Manager and go to the Home directory.
For MacOS: Open Finder, Main Menu > Go > Home.
Rename the ‘cerebro’ folder to ‘cerebro.old’;
Launch Cerebro.
If this didn't help, contact our Support: https://cerebrohq.com/en/support/.