i cant use my usb c to sd card reader

Wondering if the tips in Apple Support's online article (link below) can help:

(Eg: not all cables can transfer data ... card reader needs to be compatible with iPhone's iOS ... etc.)

See: Connect external storage devices to iPhone - Apple Support

Eg: says:

"Attach the USB drive or SD card reader to the charging port on your iPhone using a compatible connector or adapter. You may need the Lightning to USB Camera Adapter, Lightning to USB 3 Camera Adapter, USB-C to SD Card Camera Reader, or Lightning to SD Card Camera Reader (all sold separately).

Note: An external storage device must have only a single data partition, and it must be formatted as APFS, APFS (encrypted), macOS Extended (HFS+), exFAT (FAT64), FAT32, or FAT. To change the formatting of a storage

device, use the Files app or a Mac or PC."

There's more info. in the above linked article.

For a brand new device, you can contact Apple's experts if you wish:

Most Apple hardware comes with a one-year limited warranty and up to 90 days of complimentary support.

Eg: One stop for technical support, Apple hardware service, and software support. You can call Apple Support at 1-800-APLCARE

(or use the support app at the bottom of their webpage): AppleCare - Apple

or

Apple Support in countries around the world:

Contact Apple Support - Apple Support

Interesting.

What does it say when you plug the adapter with card?

Without card?

Have you tried restarting your iPhone?

Updating it?

Checking if it's not the port problem?