No audio on some phone when receiving calls since Asterisk 18.26.4 update

[Stell0]

Steps to reproduce

• Update Nethvoice to version 1.5.1.
• Configure physical phones as "Custom Devices".
• Enable TLS encryption and SRTP audio in the device configuration (including Outbound Proxy settings).
• Place or receive a call using one of these devices.
• Answer the call.

Expected behavior

The call should be established, and two-way audio should flow correctly between the parties.

Actual behavior

The phones ring and the call is established, but there is no audio transmission (one-way or no audio).
Asterisk logs show the following error: [2025-11-26 10:48:01] ERROR[1018] pjproject: ../src/pjsip-ua/sip_in ....Assert failed: !"Unable to send ACK!"

Components

• Nethvoice Version: 1.5.1
• Protocol: TLS / SRTP
• Affected Devices:
  • Grandstream GXP2160
  • Grandstream WP816 (WiFi Cordless)
  • Gigaset N670 IP PRO
  • Yealink W70B
  • Sangoma S500

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See also
https://partner.nethesis.it/t/device-criptati-in-tls-e-audio-srtp-dopo-aggiornamento-ad-1-5/
https://mattermost.nethesis.it/nethesis/pl/5wxoy4r1t7bdin9xndop5nmzda
https://helpdesk.nethesis.it/a/tickets/196041

[Stell0]

Test case:

• Reproduce the issue on a device
• Upgrade to 1.5.3-testing.2
• check the bug is no more reproducible

[viktec]

bug no longer reproducible

[Amygos]

Release nethesis/ns8-nethvoice 1.5.3