Yealink T29G Phones ringing silently in queue

[blankenshipr]

I am having the same issue as the person in this thread - however, I have tried the fix suggested, and it does not work. I have T29G phones running firmware 46.80.0.10 and 46.80.0.25 on 3CX v12.5.
https://www.3cx.com/community/threads/que-phones-do-not-ring.41851/
When a call comes into the queue for an extension with a T29G phone, the light flashes and the display shows the call, but no ringer sounds - it rings silently. This also happens when a queue call (answered elsewhere - on a T48G which does ring) gets transferred to a T29G.

I have checked the provisioning template as suggested in the other thread, but all are set to "2". Any suggestions as to what to check next?

#"X" ranges from 1 to 10;
#Configure the text to map the keywords contained in the "Alert-info" header.
#distinctive_ring_tones.alert_info.X.text = family
distinctive_ring_tones.alert_info.1.text =
distinctive_ring_tones.alert_info.2.text = external
distinctive_ring_tones.alert_info.3.text = international
distinctive_ring_tones.alert_info.4.text = national
distinctive_ring_tones.alert_info.5.text = local
distinctive_ring_tones.alert_info.6.text = queue
distinctive_ring_tones.alert_info.7.text = ivr
distinctive_ring_tones.alert_info.8.text =
distinctive_ring_tones.alert_info.9.text =

#Specify the ring tone for each text. It ranges from 1 to 8. The default value 1 stands for Ring1.wav.
#1-Ring1.wav, 2-Ring2.wav, 3-Ring3.wav, 4-Ring4.wav, 5-Ring5.wav, 6-Ring6.wav, 7-Ring7.wav, 8-Ring8.wav.
#distinctive_ring_tones.alert_info.X.ringer = 1
distinctive_ring_tones.alert_info.1.ringer =
distinctive_ring_tones.alert_info.2.ringer = 2
distinctive_ring_tones.alert_info.3.ringer = 2
distinctive_ring_tones.alert_info.4.ringer = 2
distinctive_ring_tones.alert_info.5.ringer = 2
distinctive_ring_tones.alert_info.6.ringer = 2
distinctive_ring_tones.alert_info.7.ringer = 2
distinctive_ring_tones.alert_info.8.ringer =
distinctive_ring_tones.alert_info.9.ringer =

Thank you,
Ryan