Unable to connect to Thread network (NRF52840DK)

[lindemer]

Describe the bug
The echo_client sample fails to connect to my Thread border router when compiled with the overlay-ot.conf configuration file. I have uncommented the lines at the bottom of the file to enable joiner support. This appears to be a Zephyr issue; running ot scan from the shell shows that the network is up and is joinable, but ot joiner start J01NME always results in the error message Join failed [NotFound].

ot masterkey shows an exact match to the one set on the border router. I have tried running sudo wpanctl commissioner add <eui64> 60 J01NME on the border router which returns Added Joiner <eui64>, timeout:60, PSKd:"J01NME". I'm not sure if this step is necessary, but it did not work in any case.

As a sanity check, I installed OpenThread on the same board following this Google Codelabs tutorial and am able to connect without issue.

To Reproduce
Steps to reproduce the behavior:

1. cd zephyr/samples/net/sockets/echo_client
2. Uncomment the last lines of overlay-ot.conf
3. west build -b nrf52840_pca10056 -- -DCONF_FILE="prj.conf overlay-ot.conf"
4. west flash

Expected behavior
I expected the board to join the network automatically, or at least connect after manually running the joiner commands from the shell.

Impact
I started working with BLE IPSP on Zephyr but switched to this approach after discovering a bug in the network stack (see #25444). I'm hoping one of these gets worked out soon so I can continue with my IoT project.

Environment

• OS: Ubuntu (Linux 5.3.0-51-generic) on VirtualBox
• Latest Zephyr SDK
• Zephyr v2.2
• Border router: Raspberry Pi 3B with Zolertia Firefly NCP, certified releases

Additional information
I've noticed that the OpenThread configuration values set using KConfig don't seem to impact the values shown in the Zephyr shell. Is this a known issue?

[retfie]

@lindemer try this changes into your overlay-ot.conf:

CONFIG_MBEDTLS_SSL_MAX_CONTENT_LEN=768
CONFIG_MBEDTLS_HEAP_SIZE=16384

This help me when I activate joiner support. It was related to OT_ERROR_NO_BUFS raised by OpenThread stack during joining.

[lindemer]

@retfie Thanks for the tip. I revisited the problem again today and the Zephyr board now seems to connect automatically with the unmodified overlay-ot.conf. I don't know what what caused the problem before, but I'll close this issue.