@dc42 In case it is still useful to you, you can also cause Duet to run out of buffers by slicing a large object with PrusaSlicer , having enabled the Printer Settings->General->Firmware->Supports Remaining Times option.

This option puts M73 commands into the gcode which only Prusa printers support. Duet will throw errors and the output buffers will eventually be used up. This can take a while, of course.

This was happening to me when I mistakenly selected that option, and the web interface would disconnect part way through a print, and I could not reconnect until I cycled the power on my Artemis printer. I had seen the "M73 command not supported" errors, but I ignored them until I figured out they were causing the buffers to be consumed.

In spite of having better signal strength it was still unreliable when loading the Web Control page. So I added a secondary 2.4gHz access point Using a Netgear extender connected to my gateway/router over ethernet. The Duet seems to be loading the page more reliably now, but I won't consider it solved until it works fine for a couple of weeks.

I don't know why the gateway (ATT provided BGW210) would have trouble talking directly to the Duet, but maybe it does.

Thanks, but I feel motivated to stick with the versions that SeeMeCNC recommends for the hardware that I have, if possible. They supply an install package with the following:

Firmware Version: 2.02(RTOS) (2018-12-24b1)
WiFi Server Version: 1.22
Web Interface Version: 1.22.6

I just switched my router from automatic, where it was selecting channel 1, to fixed channel 6 and it is behaving much better.

On channel 1, the Duet was reporting -66dBm signal, but on channel 6 it reports -50dBm. That's a big improvement.

If it continues to behave for a day or two, I will mark this as solved.

So I upgraded to the latest stable firmware release, RR3, and that did not help the unreliable communication.

I then went back to the latest firmware release officially supported by SeemeCNC, which is 1.21.

After copying everything on and off the microSD card, I don't see any signs of any performance issues with the card.

The Duet diagnostics shows RSSI at -66dBm, which the Duet docs say is marginal. My router is set to channel 1 for 2.4gHz.

I have ordered a wifi extender to put in the room with the printer to see if that helps.

@Phaedrux I will try loading the latest firmware this weekend, and if that does not help, then I will reformat the new card and try it. Thanks.

@Phaedrux

Both cards are fat32. If one was incorrectly formatted, wouldn't it fail completely, rather than working part of the time?

@PaulHew

I did get a new router recently, but it is actually somewhat closer to the printer, so I did not think it was a likely suspect.

I have a SeemeCNC Artemis with Duet that is 18 months old. Firmware info is below. I have been using it with the web interface exclusively.

Recently, I began having trouble loading the web control page. It usually loads just part of the page and then hangs. If I keep refreshing it 10-20 times, I can sometimes get it to load completely.

If I keep a local copy of the html page on my PC, and give it the IP address, it will connect and function in controlling the printer.

But it also frequently hangs on uploading of a gcode file. That requires multiple cancel/retries also.

These symptoms seemed to point to the microSD card interface, so I replaced the microSD card, but that did not fix the problem.
Both the original and the new cards are Sandisk 16GB Class 10 cards

Can anyone advise me on what to check next? I could pull the Duet board out and check it for physical problems.

Firmware Name: RepRapFirmware for Duet 2 WiFi/Ethernet
Firmware Electronics: Duet WiFi 1.02 or later
Firmware Version: 1.21 (2018-03-21)
WiFi Server Version: 1.21
Web Interface Version: 1.21
Web Interface by Christian Hammacher
Licensed under the terms of the GPL v3