OSError: [Errno 5] EIO

[PeterAOBell]

Attempting to run responder_test on MicroPython v1.19.1 and getting an EIO error. What am I doing wrong?

I don't believe I have altered any code (copied straight from GitHub raw).
Wired I2C connections as specified.

`MicroPython v1.19.1 on 2022-06-18; Raspberry Pi Pico with RP2040
Type "help()" for more information.

%Run -c $EDITOR_CONTENT
Testing I2CResponder v1.0.1
Scanning I2C Bus for Responders...
I2C Addresses of Responders found: [0x41]

Controller: Issuing I2C WRITE with data: [0x01, 0x02]
Traceback (most recent call last):
File "", line 141, in
File "", line 79, in main
OSError: [Errno 5] EIO

`