Hi Zeeshan,
You would need to Configure the Softphone to Login in the Sandbox Environment. Please refer to this link under the section "Configure Softphone for Sandbox" :
https://developer.ringcentral.com/library/tutorials/test-account.html
You would need to create a config.ini and paste the following :
HttpRegServer = "http://agentconnect.devtest.ringcentral.com";
PlatformServer = "https://platform.devtest.ringcentral.com"
Make sure to place this file in the "App Folder" of the RingCentral For SoftPone application :
Windows : Cntrl+F1
Mac : Fn+Command+F1
Please make sure to select UK as the region in Softphone when you Login. If you are still unable to login you could create a case by emailing the developer support team or by creating a support ticket.
If you're on a Mac, I have written this BASH utility which provides you the ability to quickly toggle between production and sandbox mode for your SoftPhone:
https://github.com/bdeanindy/ringcentral-toggle-softphone-dev-mode
Switching between environments can now be done within the softphone UI.
This is described in the Getting Started Guide's "Your Softphone" section:
From the softphone signin screen use the following key combination to bring up the environment toggle:
- Windows: Cntrl+F2
- Mac: Fn+Command+F2