Does your provider use custom image for STB? Please try this simplest method:
1. Turn on STB (power supply) without connection to Internet.
2. Page Loading Error should appear. Here will be link to System Settings.
If you don't see System Settings or it doesn't appear, it means that your provider has customized image. Please tell me which STB model do you have.
And if it doesn't work, please tell, I'll write what else you can do.