My Bambu printer will not start a print from PrintSol

Since firmware 01.08, Bambu printers have an authorisation check. A start, pause or stop sent by software is answered with "verify failed" unless the printer is in LAN Only mode with Developer Mode on. This applies over the local network and over Bambu Cloud.

What PrintSol does

• The bridge still uploads the file to the printer's SD card.
• The task stays in the queue with the message "On the printer as …: start it from the printer screen (Files)."
• You press start on the printer. When it begins, PrintSol recognises the job by its name and links it back to the task, so the queue, filament use and costs still follow.

Once a printer has refused, its card on the Printers page says "Starts from PrintSol: no" and the connection pill reads "upload only". In the Print Queue the Go button becomes Upload for that printer, so you know you will press start yourself.

Allow starts from PrintSol

• On the printer screen, switch on LAN Only mode, then Developer Mode (Settings → LAN Only → Developer Mode; the menu differs a little per model).
• Make sure the bridge has the printer's current LAN access code. If the bridge says the code was rejected, enter the new one under Edit printer.
• Press Go again in the queue.

Bambu Connect

If Bambu Connect is installed on the bridge PC and the printer is linked through Bambu Cloud, PrintSol can hand the file to Bambu Connect instead. Bambu Connect opens on that PC; pick the printer there and press Print. This route is built but has had little real-world testing.

Other refusals

• "The printer's SD card refused the file (FTP 553)": check or replace the SD card.
• "MQTT command verification failed": the same authorisation check, see above.