This occurs when the clearance between your pads is lesser than the assigned minimum clearance value. To prevent this error, make sure that the minimum clearance value is below the actual clearance value between your pads.
To check the minimum clearance on Eagle:
- In your Board editor, click DRC command.
2. The DRC window will appear. Go to Clearance tab and check the minimum clearance assigned. (The default is 6mil.)