AdvAgg is making a "Connection error" with compass/css3

When I ran!/brkeM9/ I see an connection error pointing to an AdvAgg file:…

How could I fix that? I think this kind of thing slows down site load.

Drupal core is v7.56

AdvAgg is v 7.x-2.28

I´m using theme: Pixture Reloaded v7.x-3.1

Drupal version: