# Error "SLCAN ACK timeout" what dies this mean specifically?

**URL:** <https://forum.opencyphal.org/t/error-slcan-ack-timeout-what-dies-this-mean-specifically/1561>\
**Category:** Applications & Usage\
**Created:** [January 5, 2022, 12:32pm UTC](https://forum.opencyphal.org/t/error-slcan-ack-timeout-what-dies-this-mean-specifically/1561 "2022-01-05T12:32:03Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![woody](https://forum.opencyphal.org/letter_avatar_proxy/v4/letter/w/ac91a4/32.png) [@woody](https://forum.opencyphal.org/u/woody)\
**Post date:** [January 5, 2022, 12:32pm UTC](https://forum.opencyphal.org/t/error-slcan-ack-timeout-what-dies-this-mean-specifically/1561/1 "2022-01-05T12:32:04Z")

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I’m trying to setup a UAVCAN and using UAVCAN GUI to test, but not confident of any part of the system yet. Receiving the error “SLCAN ACK timeout” every time from UAVCAN GUI

Does this mean theres a communication error between the pc and SLCAN adaptor, or SLCAN adaptor and CAN network?

fyi I’m following this guide: [UAVCAN UART NODE ; adding 3 more Serial Ports to your Flight Controller with TUNNELING - Blog - ArduPilot Discourse](https://discuss.ardupilot.org/t/uavcan-uart-node-adding-3-more-serial-ports-to-your-flight-controller-with-tunneling/37260)

Cheers,  
Woody

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**Author:** ![pavel.kirienko](https://forum.opencyphal.org/user_avatar/forum.opencyphal.org/pavel.kirienko/32/9_2.png) [@pavel.kirienko](https://forum.opencyphal.org/u/pavel.kirienko)\
**Post date:** [January 5, 2022, 1:07pm UTC](https://forum.opencyphal.org/t/error-slcan-ack-timeout-what-dies-this-mean-specifically/1561/2 "2022-01-05T13:07:34Z")

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> [@woody](#):
>
> Does this mean theres a communication error between the pc and SLCAN adaptor, or SLCAN adaptor and CAN network?

The former — the application cannot reach the adapter. This is not related to the CAN bus.

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**Author:** ![woody](https://forum.opencyphal.org/letter_avatar_proxy/v4/letter/w/ac91a4/32.png) [@woody](https://forum.opencyphal.org/u/woody)\
**Post date:** [January 5, 2022, 2:17pm UTC](https://forum.opencyphal.org/t/error-slcan-ack-timeout-what-dies-this-mean-specifically/1561/3 "2022-01-05T14:17:35Z")

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Ok, Thanks!