Wireless carriers have started enabling additional spam and robocall detection features that unfortunately can prevent calls that are forwarded to your devices from ringing. This only occurs if you are using the “What should we display on your incoming Caller ID?” with “Show the Caller’s Phone Number" and is affecting most providers that offer call routing/call forwarding services. You can find more info on this new spam and robocall detection (SHAKEN/STIR) via the official FCC website: https://www.fcc.gov/call-authentication 

If you are experiencing this issue we recommend trying either one of the following fixes:

1. Changing your incoming caller ID setting to show your Virtual Phone Number instead of the caller's phone number. Changing this setting will force all incoming calls to appear as your Virtual Phone Numbers and reduce the number of calls that are blocked from your device's Scam Blocking feature. Our full guide on how to change this setting can be found here: https://support.talkroute.com/hc/en-us/articles/214707177-How-to-Change-the-Incoming-Caller-ID

2. Disable the Scam Blocking or similar feature on your device. This will allow incoming calls from any number on your device if calls are falsely getting blocked from this feature. The setting can typically be found under the carrier app or via the settings page of your phone. Any incoming calls that your device would typically block will now be labeled as "Scam Likely" or something similar. If this feature is not present on your device, please see option 1 above.

Example from a T-Mobile Phone: