How to get access token in Microsoft Dynamic CRM REST API for get contacts throw API

I unable to get the Microsoft dynamic CRM client details in REST API - palmtreeinfotech6.api.crm8.dynamics.com/.../contacts(2b8fc8ca-86cd-e611-8109-c4346bdc0e01)

I already asked in this CRM froum - community.dynamics.com/.../221682

Is this an issue because
1. we are running this from India and not US
2. we are running without 2 factor authentication (2FA) enabled

because you moved to a new location, you must use multi-factor authentication to access