When using Salesforce for Outlook Lightning edition click to dial is not functional nor can RingCentral desktop allow click to dial on phone numbers inside of Outlook. This was achieved years ago with TAPI in Outlook 97.. Perhaps the focus needs to shift to key functionality and not Glip.
Click to dial is indeed a feature of the RingCentral for Salesforce app that works with both the classic view and the new Lightning view. There are more details on our guide for using RingCentral for Salesforce.
Could you provide some screenshots of what you see when a number is displayed in Salesforce? Are any of your coworkers that use the same system experiencing this issue in the Lightning interface?