First of all, our overlays are not available for macOS right now!
Make sure you are on the latest version.
You can check if you're on an outdated version by heading to Settings > General > Blitz (Version), and compare that to the latest version available on our download page
If Step 1 doesn't resolve:
If you have and use applications like Rivatuner and/or MSI Afterburner, disable or uninstall them. Unfortunately, these applications can conflict with our overlay.
Ensure you have the overlay enabled. Move to Overlays and enable the respective overlay option.