When we turn on the Brand switch in the Globals, “The preview could not load due to the iframe response being incomplete…most often related to plugin conflict, [etc.].” message window is displayed and the page shows an endless loading animation.
This occurs when editing any page.
This occurs with all plugins deactivated.
This occurs with either SVG or Webfont selected.
I’ve cleared the Cornerstone system cache.
I can’t think of anything else it could be. Maybe the font is corrupt?