I was using the Ring Central Call app from app Exchange in my salesforce, after following all steps for integration the when i check for the app the in lightning the dialer noto loading.
Using the RingCentral Phone for Desktop, you can dial or receive test calls, send and receive test SMS or Fax messages in your sandbox environment.
Download RingCentral Phone for Desktop:
Tip: switch to the "sandbox mode" before logging in the app:
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