Chrome Extension troubleshooting
If you're not seeing any active tests when in youtube studio an API key wasn't properly created for the extension, here's some steps you can take to try and create one:
uninstall extension
make sure any ad blockers are disabled
or allow app.thumbnailtest.com and studio.youtube.com
reinstall extension
open app.thumbnailtest.com
wait on thumbnail test for 20 seconds to make sure an API key is generated successfully (there’s no visual indication currently but it’s being worked on)
then open YT studio making sure you’re signed on the correct channel
the overlay should slide in if you have active tests then slide out of screen if everything synced correctly
refresh test page and data should be there
Click on the extension in the toolbar or in the extension list and the settings should popup (Picture below)
Click on "Remove key"
Open ThumbnailTest by going to https://app.thumbnailtest.com
Wait for the page to fully load
Click on the extension again and it should show that it is connected again.
uninstall extension
make sure any ad blockers are disabled
or allow app.thumbnailtest.com and studio.youtube.com
reinstall extension
open app.thumbnailtest.com
wait on thumbnail test for 20 seconds to make sure an API key is generated successfully (there’s no visual indication currently but it’s being worked on)
then open YT studio making sure you’re signed on the correct channel
the overlay should slide in if you have active tests then slide out of screen if everything synced correctly
refresh test page and data should be there
How to get new API Key for Chrome Extension
Click on the extension in the toolbar or in the extension list and the settings should popup (Picture below)
Click on "Remove key"
Open ThumbnailTest by going to https://app.thumbnailtest.com
Wait for the page to fully load
Click on the extension again and it should show that it is connected again.
Updated on: 07/06/2025
Thank you!