Could not fetch serial number

[mhalhead]

Describe the bug
The add on worked previously, occasionally "crashed" but nothing too serious. However, it now won't start with an error message ERROR:
Could not fetch serial number

I have increased the debug to "trace" but that doesn't provide much more information.

Application version
1.2.3

Texecom alarm type
Premier Elite 64
Firmware version: 4.x

Home Assistant version
Home Assistant:
Core: 2024.8.2
Supervisor: 2024.08.0
Operating System: 13.0
Frontend: 20240809.0

Debug log
2024-08-19 08:08:22 - INFO: Starting texecom2mqtt v1.2.3 (Node v16.13.0)...
2024-08-19 08:08:22 - INFO: Connected to alarm, sleeping for 2 seconds...
2024-08-19 08:08:22 - TRACE: Received data chunk of length 2
2024-08-19 08:08:24 - DEBUG: Executing serial number command
2024-08-19 08:08:24 - TRACE: Received data chunk of length 2
2024-08-19 08:08:24 - ERROR: Could not fetch serial number