Hello, I can't seem to round these corners:

It's a joist hanger, like this:

.skp file attached:
joist hanger.skp
I'm really not sure where I go wrong. Any help is appreciated!
Hello, I can't seem to round these corners:

It's a joist hanger, like this:

.skp file attached:
joist hanger.skp
I'm really not sure where I go wrong. Any help is appreciated!