Intermittent inbound queue calls drop after ~1 second – “Call lost in queue” (Error 105) – V20 U8 (Azure)

[Henrico JvR]

Hi all,

I’m experiencing an intermittent issue with inbound calls to queues and hoping for some guidance.

Issue​

External inbound calls (via call script → digital receptionist → queue) will occasionally:

• Ring for ~0.5–1 second on agent softphones
• Then immediately drop / become unavailable to answer

This happens once or twice per day and affects all queues intermittently. The same queues otherwise work perfectly most of the time.

Key detail (important)​

In the 3CX logs, the system shows the call:

• Ringing for the expected duration (e.g. ~10s, then failover to next agent)

However in reality:

• Agents only see ~1 second of ringing
• Then the call disappears
• They cannot answer it

Event log message​

Consistently shows:

• “Call lost in queue” – Error 105

Environment​

• 3CX Version: V20 Update 8
• Hosted on: Azure
• Queue strategy: Prioritized Hunt (all queues)
• Agents: Softphones (desktop/mobile apps)
• Routing: Digital Receptionist → Call Script → Queue
• Call type: External inbound only

Notes​

• Fully intermittent and difficult to reproduce
• No full outages — just sporadic failed queue calls
• Not isolated to any specific queue or agent

 

[KyriacosS_3CX]

Hi,

I've send you a direct message, please take a look.