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. To do this:
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 the Cerebro
If this didn't help, contact our Support: https://cerebrohq.com/en/support/