Mbed OS on ST-Nucleo-L476RG, problem with serial port

No, USBRX,TX are connected to UART2, I used D8 and D2 pins which are connected to UART1. I’ll do some tests and will let you know… Could it be a clock problem? But then why the virtual serial over USB is ok?
Other than that it seems that mbed OS works good on this STM32L4, I’m seriously considering to develop my project on mbed OS rather than classic