If you are experiencing an error with the Chrome extension, the fix is typically to make sure you're logged out of your Wordpress admin and logged into Ezoic in a separate tab. Then, deactivate your extension, clear cache and cookies, and reactivate it.
However, if this does not work, here are some things to check for if you still cannot activate the Ad Tester chrome extension (see step 4 onwards):
1. Are you logged out of your Wordpress admin?
2. Is Ezoic active? Are you logged into Ezoic?
3. Try deactivating the extension, clearing cache and cookies, and reactivating it
4. Have you installed the most up to date version of the Ad Tester extension from the Chrome Web Store?
5. Try uninstalling the extension and re-installing it
6. Double check you are using Chrome as a browser
7. Double check no other extensions are blocking this extension
8. Check you have the most up to date version of Chrome