Skip to main content
Phone carriers may mark certain phone numbers as “Spam Likely.” This leads to low outbound call pickup rates and can sometimes result in telephony providers banning your number or account.

​
Check Whether Your Number Is Marked as Spam

Check your outbound call log for SIP error code 608 — this indicates a call was rejected due to a spam-likely flag. Note: not all spam-rejected calls will show 608. External services to check your number’s reputation:
  • Nomorobo — Use the app or API to check against their database
  • IPQualityScore — Check phone number reputation score
Each carrier maintains its own rules and database, so no tool gives a perfect result across all carriers.

​
Actions You Can Take

UponAI provides two services to improve your call pickup rate:

Verified Phone

Register your number with phone carriers so it won’t be marked as spam.

Branded Call

Callees see your business name instead of an unknown number.

​
iOS 26 Call Screening

iPhones on iOS 26 may deploy a call screening feature where Siri asks unknown callers to provide their name and reason for calling before connecting. To pass this screen, add handling to your agent prompt: 
## FAQ
Q: Hi, if you record your name and reason for calling, I'll see if this person is available
A: In one sentence, introduce yourself and explain why you are calling. <wait for response>