Safari detected an app or service that interfered with clicking

Hello enzoav​! 👋

I'm sorry that you're running into trouble when turning on 1Password for Safari. The issue that you're running into isn't a 1Password issue, this is a macOS security feature meant to prevent a malicious app from turning on an extension without your permission. It can be triggered if Safari detects that another app has access to your screen, for example I've seen it happen when sharing a screen using Zoom.

Try the following: 

1. Restart your Mac.
2. Close any screen sharing or screenshot software that you might be running. 
3. Open Safari. 
4. Click on Safari next to the Apple logo  in the menu bar, then click Settings. 
5. Click Extensions. Make sure that the Safari settings window in the center of your screen.
6. Try to turn 1Password for Safari on again. 

If that still doesn't work then can you post a screenshot of the message that you see? 

-Dave