HMC5883L compatability/use

Hello,
I'm relatively new to Arduino, but not so much to coding. I'm trying to use the HMC5883L magnetometer (using this library: GitHub - sleemanj/HMC5883L_Simple: Simple to use Arduino library to interface to HMC5883L Magnetometer (Digital Compass)) with an adafruit feather 32u4 but it does not get past the initialisation stage. However if I connect the HMC5883L to an arduino uno it works straight away with no issues. I'm not sure if this is just board incompatibility or there is some differences in code between different board types.

Any pointers or ideas as to why it's not working on the feather would be greatly appreciated!

For informed help, please read the "How to use this forum" post and follow the directions.

As your chip is a I2C device my guess is a wrong wiring. For a ATmega32U4 device SDA and SCL are not on A4/A5! Post a wiring diagram.

pylon:
As your chip is a I2C device my guess is a wrong wiring. For a ATmega32U4 device SDA and SCL are not on A4/A5! Post a wiring diagram.

Something so simple! I did not realise SDA & SCL were not on A4/A5. Thank you very much!