FX_IO_ERROR - STM32U5 with SD Card

[MGuth.1]

Hi all
I'm currently working on getting the SD Card Interface (SDMMC1) to run on my Nucleo U575 board. I'm adapting the Fx_uSD_File_Edit Example of the STM32U575I-EV board.
I'm running into problems when it comes to opening the SD Card media. In fx_media_open.c, media_ptr -> fx_media_driver_status has a value of 144 (FX_IO_ERROR). I expect the value should set be back to 0 (FX_SUCCESS) in (media_ptr -> fx_media_driver_entry) (media_ptr) (at comment "/*Invoke the driver to read the boot sector.*/). In my case, it isn't reset to 0 but stays at 144 instead.
Unfortunately I can't find the linked function to have a deeper look debugging. Could someone please assist and tell me where to find this function? Or maybe even telling me, what setting the error could be caused by :D

cheers

[MGuth.1]

This may was just to some wrong/bad connection of the breakout board. Didn't change anything in the code, now it works :)