Recently, our directory team thought 1pm on a Wednesday was the perfect time to delete legacy Security Groups throughout the domain, without prior heads up to the affected teams. From that point, Nintex workflow designer stopped working.
"Some or all identity references could not be translate" appears when you attempt to save or publish workflow and your workflow actions do not load in the left hand pane. if you look at the browser console (DevTools) you'll notice 2 errors related to the identity translation
if publishing/saving workflow - soaperverServer was unable to process request. ---> Some or all identity references could not be translated.
if attempting to build workflows - Actions won't load, Console (DevTools) has errors starting as Request error has occured. status: parseerror. message: SyntaxError: Unexpected Token < in JSON at position 2. readyState: 4 statusCode 200: etc
As explained by ButlerJ in his related post simply remove any Security group that has recently been changed to a Distrobution List or change it back to a security group.
In our case, we couldnt create or publish any workflows throughout the farm. Our problem lied within Central Administrator>Nintex Administrator>Action Settings. Many of our custom settings and connectors were locked down to security groups (by the old Admin); the same security groups that have since been deleted. similarly to ButlerJs' steps, remove the deleted security groups, then re-add the replacement security group (or leave it as is).
This is caused by the workflow (or workflow actions in Central Admin) being unable to resolve a group that was recently Deleted or changed from a Security Group to Distrobution List.