Last updated: April 2026
If you are making outbound calls and receive a Network Blocked notification or a 603 response code, the call was likely intercepted by a carrier or call analytics provider before reaching the intended recipient.
Why was my call blocked?
Carriers use automated analytics to identify possible robocalls, spam, or scam activity. Your call may be blocked for reasons such as:
- High call volume: A large number of calls placed in a short period from the same number.
- Short call duration: A pattern of calls lasting only a few seconds.
- Consumer reports: Recipients previously reported the number as spam or scam likely.
- Caller ID reputation: The calling number has a poor or unknown reputation with analytics providers.
How to resolve blocked calls
If your legitimate business calls are being incorrectly blocked or labeled as spam, submit a redress request with the appropriate carrier or analytics provider.
Recommended next steps
We recommend registering your business numbers with Free Caller Registry, First Orion, and Hiya. This helps distribute your business information to major call analytics providers.
- Make sure your Caller ID/CNAM accurately reflects your business name.
- Avoid sudden, high-volume calling patterns from new or low-reputation numbers.
Important note
Call blocking and spam labeling are controlled by downstream carriers and third-party analytics providers. Submitting a redress request does not guarantee immediate removal, but it is the recommended path for correcting false-positive blocking or spam labeling.