Having Same issue. Page not found.
Cannot get access token from api.
Using Version 1.8.1 on IIS 8.5 PHP 5.6 …
I checked;
IIS url rewrite rules, they all importted from .htaccess as guided
.
IIS max querystring size : its 4096
Open Debug mode, see the POST error, page not found. no more details as the sshot.
Set everything as you guide for Postman :
What you offer for me next??
The other functions of CMS is working fine.