I'm using KeystoneJS version 4.0.0 beta-5, installed on my local server.
Installation is carried out according to the instructions keystonejs.com
In general, everything works fine, except for saving in the browser Safari Version 11.1 (13605.1.33.1.4).
When I press the save button in the Admin panel, saving goes on forever, in other browser's all works fine.
Error screen in Safari:
Saving progress screen in Safari:
Success screen in Chrome:
Does anyone help with this problem?