Can't connect to my Ender 3 via OctoPrint

[Hristiyan_Hristov]

What is the problem?

I can't connect to the printer using OctoPrint. Getting this error:
Offline (Error: No more candidates to test, and no working port/baudrate combination detected.)

What did you already try to solve it?
I tried manually selecting all baudrates, also tried to update octo and restarted both the pi and the printer.

I also tried running lsusb and I saw that there is no change once the printer is connected with the USB cable and once I disconnect it.

I also removed the tape which i put on the USB cable (in order to resolve the 5v problem), but still can't connect any new device. I will try with a new USB cable later today

Logs (syslog, dmesg, ... no logs, no support)
octoprint log - https://paste.ofcode.org/njSbZU2vrbucSmmFRcErqM

Additional information about your network (Hardware you are trying to connect to, hardware you are trying to connect from, router, access point, used operating systems, ...)
Ender 3 PRO
This is the first time I'm connecting it, I'm on the same network, the Pi is a bit further from the router but I doubt this would be the problem.

[Ewald_Ikemann]

Hello @Hristiyan_Hristov!

You have this in your log:

2020-09-03 21:18:31,811 - octoprint.plugins.pi_support - WARNING - This Raspberry Pi is reporting problems that might lead to bad performance or errors caused by overheating or insufficient power.
!!! UNDERVOLTAGE REPORTED !!! Make sure that the power supply and power cable are capable of supplying enough voltage and current to your Pi.

You also might have a flash icon at the navbar:

Restart the Pi without the printer connected. If that icon does not appear try this:

Put tape on the 5V pin - Why and how

First of all this whole tutorial isn't a mandatory mod - you just need it if you run into issues (weird things are happening and you've already ruled out the more common suspects) or if the always running fan and illuminated display (even when the printer is turned off) disturbes you. I'm starting with the why part: If you connect a 3D printer via USB to your Raspberry Pi it can lead to all sorts of power related issues. Most of the time those issues occur only if you turn on your pi before…

If it still appears, you should look for a better power supply (not charger)

[Hristiyan_Hristov]

Hello,
Once I put the tape on the USB connector the problem with the undervoltage disappeared.

I just tried one more USB cable and it's working now. Thanks a lot!

[Ewald_Ikemann]

Great! could you please do this:

PSA: Please mark the solutions to your topics as such

All topics you create in this category can be marked as "Solved" by clicking the little icon under the post that contains the solution: [image] Please make heavy use of it. Marking a topic as solved allows others to quickly see that a solution has been found and also displays the solution prominently right in the start post so that others with the same problem may find it easier, without having to scan through the whole thread. Thank you!

[Hristiyan_Hristov]

Did it, thanks !

[Junopapa]

This tape trick did not help on my Ender-3 Pro with the same "Offline (Error: No more candidates to test, and no working port/baudrate combination detected.)". I tried two different cables.