Cannot connect printer after 1.4.2

So where is the issue?
When you know where to set them manually, just do it.

Solving an issue usually needs more, like logs...

new to this but updating the artillery sw1`s pi3b and octoprint creates for me an issue where its now totally refusing to connect, with my limited experience ive tried changing a few things as above and nope nothing, thankfully ive not tried it with the other three printers - cr10 mini plus a pair ender 3 which are as normal connecting without issue so at this point in time none of the others will be getting this update, thankfully the sw1 has usb stick access as well as tf card so im not semi stuck, ive tried also the obvious - the cables

Just to help understand that there does seem to a pattern with this issue and the 1.4.2 upgrade, I had the same thing happen. No problems just prior to upgrading, then this, immediately after the upgrade:

Changing monitoring state from "Detecting serial connection" to "Error: No more candidates to test, and no working port/baudrate combination detected."
Changing monitoring state from "Error: No more candidates to test, and no working port/baudrate combination detected." to "Offline (Error: No more candidates to test, and no working port/baudrate combination detected.)"

I looked at the changed files, and as @foosel pointed out, this upgrade shouldn't affect that. So, my assumption was it was an upgraded and/or incompatible plugin. I disabled all third-party plugins I had:

  • Bed Visualizer (0.1.14)
  • DisplayLayerProgress Plugin (1.23.0)
  • PrintTimeGenius Plugin (2.2.5)

No change. So, I completely uninstalled and cleaned up data for those plugins. Rebooted - no change.

I then disabled all bundled plugins, rebooted, still no change.

I SSH'd into the Pi and ran:

dmesg | grep tty

To make sure the serial port (ttyUSB0) showed up. Sure enough - it did NOT.

Here's the thing. I use a modified USB cable that prevents the Pi from powering my Creality controller through the USB port. (It is a quirk of the model that, so long as the USB port on the printer's controller, the screen backlight will stay lit.)

Swapped out the USB cable for an unmodified one (i.e. +5v, Gnd, D+, D1). Fixed it straight away.

However, as a software developer myself, I'm not satisfied with that solution. This is clearly something at the OS level since Linux didn't recognize the port. I can understand that. What I don't understand is why it had no problem before the 1.4.2 upgrade, but did immediately afterward.

When I get a minute, I'll dig deeper to see if I can't sort it out. For now, everything works great, using the regular data cable.

But, for anyone experiencing this problem, I would suggest running dmesg, as I did above, and see if your port shows up there. If not, the problem isn't with Octoprint - at least not directly. I would be curious, however, if rolling back to an earlier version corrects the problem. I'm betting not, but that would be interesting.

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Same issue here. No issues until I upgraded to 1.4.2 this morning.

Then the following error

Changing monitoring state from "Offline" to "Detecting serial connection" Performing autodetection with 0 port/baudrate candidates: Changing monitoring state from "Detecting serial connection" to "Error: No more candidates to test, and no working port/baudrate combination detected." Changing monitoring state from "Error: No more candidates to test, and no working port/baudrate combination detected." to "Offline (Error: No more candidates to test, and no working port/baudrate combination detected.)"

I did rollback to 1.4.1 immediately and nothing changed. Have also rebooted octoprint into safe mode with no change.

I only have a couple plugins so I didn't even bother going through them

I ran dmesg | grep tty

and got the following feedback

pi@octopi:~ $ dmesg | grep tty [ 0.000000] Kernel command line: coherent_pool=1M bcm2708_fb.fbwidth=656 bcm2 708_fb.fbheight=416 bcm2708_fb.fbswap=1 vc_mem.mem_base=0x1ec00000 vc_mem.mem_si ze=0x20000000 console=ttyAMA0,115200 console=tty1 root=PARTUUID=6c586e13-02 roo tfstype=ext4 elevator=deadline fsck.repair=yes rootwait [ 0.001260] console [tty1] enabled [ 1.041359] 20201000.serial: ttyAMA0 at MMIO 0x20201000 (irq = 81, base_baud = 0) is a PL011 rev2 [ 1.936436] console [ttyAMA0] enabled [ 6.768034] systemd[1]: Created slice system-getty.slice.

I also was using a modified usb cable for my cr10 v2 for the same reason. I switched back to an intact one just now and no change.

Still no connection for me.

I'm willing to work with the developer to debug as I have no problem just printing from sd card for now

My hunch (unproven) is that the upgrade to 1.4.2 updates something in Linux that prevents it from recognizing ttyUSBn for whatever reason. So, rolling back to 1.4.1 wouldn't fix it, since it has nothing to do, directly, with OctoPrint. I haven't had a chance to dig into what system changes might have sparked the issue.

But, I'm really surprised that swapping cables didn't do the trick. Even after rebooting?

Not really the case - all OctoPrint does, is install the new version as a python package - it has no way to touch the underlying system

The most common reason for issues after updates is corruption. Try (if you're using OctoPi) running ~/oprint/bin/pip install --force-reinstall --no-cache-dir octoprint to fully reinstall it.

That's not entirely true. It may be that it does not touch the underlying system, but it is not true that is has no way of doing so. We've done a lot of Python development, and run into this more often than we should. It usually has to do with a dependency of a dependency of a dependency, etc. that causes the problem.

OctoPrint, itself, is not causing this. But, the act of updating is. I am not seeing any dependency that is obviously the problem, either. (Haven't looked into RSA and itsdangerous, but I wouldn't suspect these first.) But, here's what I do know:

I restored a snapshot of my Pi taken back in April (1.4.0). Everything worked, as it did in April. I then did nothing but update to 1.4.2, and the ttyUSBn was no longer recognized. Rolled back to 1.4.0 and 1.4.1 to no effect.

Also, the failure to mount ttyUSBn isn't even an OctoPrint issue. The OS does not recognize the serial port, whether OctoPrint is running or even installed. It does, before upgrading, it doesn't after upgrading - confirmed twice.

I honestly don't think there is anything for the developer to do, here, but it is a reproducible issue that seems to affect some setups in a fairly consistent way. Since I am able to reproduce it, I'll look at it more, when I have time. Should be pretty easy, at this point, to see exactly what is different after the upgrade.

trying the octopi force reinstall now. I've got nothing to lose really. Didn't have any significant plugins installed. was just happy to print and monitor without running outside to the shop all the time. I'll update if i make any progress

nope no change

Here's more info. When I first installed octoprint and octopi with my new printer I originally worked fine, then I installed a couple plugins and it broke. Giving me the "failed to autodetect serial port error" I can't remember how I fixed it but it involved some commands and it all was working fine for a couple months. Fast forward to today and it will no longer connect with nothing changed except the update.

So I rebooted my pi with my original sd card image from a couple months back and immediately got the failed to autodetect serial port error. Not sure what version it was but maybe 1.3.something.

I did nothing except update octoprint to 1.4.2. Now immediately after the update its this error again.

Maybe that helps, maybe it doesn't...maybe it will help somebody who stumbles across this down the road. ANyways I'll keep updating this thread if i get it fixed

I guess I worded that wrong, you're right - yes it could do, but OctoPrint's code does not try to. It could be a dependency of a dependency like you say, that creates this issue. Without digging into the dependency tree hell, I couldn't tell you!

I'm probably also partially blinded by the number of people who end up with 'my OctoPrint's broken' after they update because the install was corrupted. So many after the 1.4.1/2 update with corrupted installs, which the command above fixed it.

at least for me
~/oprint/bin/pip install --force-reinstall --no-cache-dir octoprint
fixed it!
i did also run ~/oprint/bin/pip --upgrade pip or what ever the pip upgrade command was because it was an old verison

edit never mind.. it started printing and then the print process was stopped because lost connection or something

I was experiencing the same issue after upgrading to 1.4.2

Connection just magically started working after changing USB port on RaspberryPi and resetting the Serial Port and Baudrate to AUTO.

I'm running a test print now.

Edit
Test print worked, but lost ability to connect to OctoPrint server via a web browser shortly after the print began. Test print finished successfully.

I had to restart the server in order to connect to OctoPrint server via a web browser, but was again experiencing connectivity issues with the 3D printer.

I reset the serial and baudrate to auto, shutoff the RaspberryPi, changed the USB port, and started server again. This again allowed OctoPrint server to successfully connect to 3D printer.

Second print running now.

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Throwing in my two cents, I'm also having the same problem.

I've had a part in my printer (Ender 3) broken for a while, so I haven't tried using octoprint for a couple of months. Now that I've fixed it, I'm getting the

 Offline (Error: No more candidates to test, and no working port/baudrate combination detected.)

error.
I've tried: connecting to a different printer mainboard, using a different usb cable, using a different usb port, rolling back to an earlier version of octoprint, manually re flashing octoprint, using the force-reinstall command via ssh. Attached are my logs (main, and serial communication).

Any help would be super appreciated. I want so desperately to finally have my 3D printer back.

Thanks for your time!
serial.log (1.2 KB) octoprint.log (101.0 KB)

Is there a serial port listed that would allow you to manually set the port and baudrate?

Hi Jneilliii,

I can manually set the buad rate (although no baud rate succeeded when I tried setting them manually) but only "auto" appears under Serial Port.

Thanks for your help!

So that means octoprint is not aware of the serial port that your printer is connected on. This may mean it needs to be manually added in the additional serial ports option in order to be recognized. If you SSH to your pi and run the command dmesg | grep tty what is returned?

This thread may also be helpful, and the connection may also be listed with dmesg | grep usb.

Here's what I get with dmesg | grep tty.
Not sure how to interpret those results.
And once again, thanks for your help, it's very much appreciated!