Hey there Gb__1234,
Thanks for reaching out to the Apple Support Communities.
To get started, have you given the steps in the 'Related Article' under the "If your device doesn't charge, loses charge, or charges slowly" section a try: How to use the 35W Dual USB-C Port Power Adapter - Apple Support
If your device doesn't charge, loses charge, or charges slowly
Your device might need more power than the power adapter can provide across one or both ports. Try these solutions:
* Try charging a single device to ensure that your device can get the most power from your power adapter.
* If you’re charging only a single device, unplug any charging cable that is not in use.
* Try a different charging cable—preferably the one that came with your device.
* Make sure that your devices don't need more than 35W of power, which is the maximum amount of power that the power adapter can deliver.
* If your device still isn't charging, your device may not be compliant with latest USB PD specifications.
If your device still won't charge after trying the above solutions, contact Apple.
Per the steps above, it is recommend to test the issue with the charging cable that came with your iPhone. If you don't have the charging cable that came with your iPhone, would you have access another Apple certified charging cable you could test with?
If the issue persists when testing the issue with another charging cable, and after going through the steps above. We would recommend reaching out to Apple Support using the 'contact Apple' link above. You can also reach out at this link here: Get Support
We hope that's able to help.
Take care!
