Sermoon D3 Pro: "Printing Failed" silently when sending job via LAN in Creality Print 7.x

[Jeri436]

Is there an existing issue for this problem?

• I have searched the existing issues

CrealityPrint Version

7.0/7.1

Operating System (OS)

Windows

OS Version

Windows 11

Additional system information

No response

Printer

Sermoon D3 Pro

How to reproduce

1. Add Sermoon D3 Pro via LAN (device is visible and detected correctly)
2. Slice a model
3. Click "Send to Device"
4. Software navigates to the print details view

Actual results

Actual results
Print immediately shows as "Printing Failed" with no error message or additional information. This happens consistently on both version 6 and 7.

The debug log shows the following at the point of failure:

[error] Slic3r::GUI::CxSentToPrinterDialog::fire_print_send_event: frontend_data - {"command":"send_gcode","ipAddress":"192.168.178.33","moonrakerPort":0,"oldPrinter":true,"plateIndex":0,"uploadName":"obj_1_Foot - NR200P.stl_PLA_4m55s.gcode"}
[error] Slic3r::GUI::CxSentToPrinterDialog::fire_print_send_event: error_code - OK m_print_send_fired false
[error] send frame error: Eine bestehende Verbindung wurde softwaregesteuert abgebrochen

[error] Slic3r::GUI::CxSentToPrinterDialog::fire_print_begin_event: RAW json_data - {"command":"send_start_print_cmd","data":{"allPlate":false,"color_match_info":"","open_cfs":0,"print_calibration":1,"printer_ip":"192.168.178.33","upload_gcode_name":"obj_1_Foot - NR200P.stl_PLA_4m55s.gcode"}}
[error] send frame error: Eine bestehende Verbindung wurde softwaregesteuert abgebrochen

Device entry in deviceInfo.json as auto-detected by the software:
{
"address": "192.168.178.33",
"connectType": 3,
"moonrakerPort": 0,
"oldPrinter": true,
"model": "Sermoon D3 Pro"
}

Expected results

The print job should be sent and started on the printer successfully

Project file & Debug log uploads

logs.zip

Checklist of files to include

• Log file
• Project file

Anything else?

The device is correctly discovered and listed in the software. The failure occurs silently at the point of sending the print job. No error message is shown besides "Printing Failed".

[Jeri436]

What i notice while expertimenting with different version. The last major version (6.3) still works without any issues with the printer for me.