Code stucks at MX_USB_DEVICE_Init();

[GunkutA]

Hello, I use STM32F103C8Tx but USB communication does not work as it intends to. Sometimes codestuck at MX_USB_DEVICE_Init(); function.. More spesifically  it gets stuck at

USBx->BTABLE = BTABLE_ADDRESS;

line inside of MX_USB_DEVICE_Init();

When I connect other side of the USB Communication, it gets fixed.

What might be the reason behind that? So do I need to connect USB device, or will it stuck in MX_USB_DEVICE_Init(); function?

Note: It is not related to interrupt priority.