Can not make calls from softphone sandbox

Could you provide some more detail about the issue you're seeing please?

1. What do you mean when you say "web"? Do you mean: an integration you installed from App Gallery, while developing a WebRTC application, or something else?

2. Are you using the softphone in development/sandbox mode, or is this with your production account?

3. Are you developing an application or integration using the Connect Platform API/SDKs and running into this issue, or is this with your RingCentral account in general?