[Build Volume Error When Using Support Eraser]

Thanks, that did it!

[Build Volume Error When Using Support Eraser]

In case you're curious, I'm printing it vertical likes this because I'm using a rainbow filament and want the color gradient in that direction.

[Build Volume Error When Using Support Eraser]

I am trying to remove some unneeded supports from my 3D print in Cura, however, I get this error:

 

Part I want to add a support blocker to:

 

 

After adding support blocker:

 

 

All the tutorials I've seen make it seem like this is supposed to be easy.  Just click on support blocker and place.  Is there a setting I need to uncheck somewhere?