Can't seem to communicate to print

[masterthimios]

Great great project! I loved the idea and ordered the parts.

I have configured everything and it says it is connected to the wifi and MQTT server but when I do MQTT publish action it does not print at all!
Everything is correctly configured. I don't seem to be publishing correctly to MQTT!
I use the topic /printer/thermal and a text payload of two words (in the developer tools > services tab) and I get nothing from the printer.

How do I troubleshoot that.

[chrisfu]

Exactly the same issue here. GOOJPRT QR204 printer, LoLin NodeMCU v3 with RX and TX wired to D1 and D2 respectively. Everything is powered, WiFi connected, MQTT active with the paper checks happening every 10 seconds.

Checked and rechecked my soldering, no bridges and solid connections to the correct points. Powering the NodeMCU via VIN so can't really plug in a USB to debug without risking blowing the board.

Feels as if the MCU isn't communicating with the printer, though everything is in place for that to happen.