Welcome to the RingCentral Community

The current issue that the RC app in sandbox fails to save the emergency address is not yet fixed. Here is a workaround solution.

1. Login the sandbox account service web

2. Select the user (the one you login the RC 'devtest' app)

3. Select the Phones & Numbers and select the 'Phones' tab

4. Remove the RC app as a device if you have set it up earlier.

5. Click the 'Add Phone' button and at the second step 'Select devices', choose 'Other phones' then select the 'Existing phone'

6. Move on to select phone number then at step 4, provide the emergency address

7. Complete other steps then save and go back to the RC 'devtest' app to make a call.

Yes, you can set up multiple sandbox account and make test calls between them.