BLUENRG stuck when writing BLUE_CTRL registers

[MRey.1]

I'm working on a custom board with a BLUENRG-2. I'm able to flash and erase with the UART and the SWD pins, but none of the programs work. When I debug it step by step, I find out that all programs hang on this line, when it writes on the BLUE_CTRL register:  

Anyone knows what could be causing this issue?

[Winfred LU]

Please check the high speed crystal.

The code is to configure crystals accordingly and to wait until the crystal oscillators are ready.

[MRey.1]

Sorry for the late response. Yes, indeed it was the crystal network. The crystal ground was floating, it was solved when I connected it to the main ground