Calls to external numbers not completing, marked as spam, ringing busy, or going straight to voicemail.
Phone service providers have been working to implement a new technology called, Stir/Shaken. It's intended to fight robocalls and other fraudulent calls. This new technology certifies a phone number as legitimate as a call passes from one carrier to another.
The tool is new, and if you're experiencing trouble completing calls to certain carriers, it is most likely that your number has been inadvertently flagged as problematic by the cell phone service carriers when they receive the call. It would be similar to an example of a legitimate email getting flagged as spam by an email filter. To help address these occurrences, mobile carriers have set up portals by which you can register your number so they can whitelist it to allow your calls to their services.
Below are websites where you can submit whitelisting requests:
- AT&T: Information on Digital Phone Call Protect service, call blocking, and other features.
- CenturyLink: Customer tips and tools to block unwanted calls.
- Comcast: Call blocking options for XFINITY Voice subscribers.
- Frontier Communications: Consumer options for call blocking tools and services.
- Spectrum: Guide for using Nomorobo service to block robocallers.
- Verizon: Customer options for stopping unwanted calls to residential lines.
For more call blocking tools and resources follow the link below: