The CCP softphone needs outbound UDP 3478 to the Region's TurnNlb endpoints; without it agents see Failed to establish softphone connection and miss calls.

Checked 2026-09-25

Vendor
Amazon Web Services
Product
Amazon Connect
Subsystem
agent phone
Deployment
multi-tenant
Region
not restricted
Release range
current as of 2026-09-25
Checked
2026-09-25

Sources

Cite this note

APA

WarmTransfer. (2026, September 25). Connecting Unified CM to Amazon Connect: source note cucm-with-amazon-connect-softphone-udp-3478. WarmTransfer. https://warmtransfer.net/knowledge/claims/cucm-with-amazon-connect-softphone-udp-3478

BibTeX

@misc{warmtransfer-claim-cucm-with-amazon-connect-softphone-udp-3478,
  title  = {Connecting Unified CM to Amazon Connect: source note cucm-with-amazon-connect-softphone-udp-3478},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/claims/cucm-with-amazon-connect-softphone-udp-3478},
  note   = {Source note cucm-with-amazon-connect-softphone-udp-3478, checked 2026-09-25}
}

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