But I know that the communication works properly in normal working condition (not in debugging), so, somehow the debugging mode affect the communication. how the debugger affect it?

Is there anything else I can do except for checking the lines?how debug mode can affect the communication? maybe I can change the clock or the bound rate in some way that can help? 

I didn't check

the DR register not get the data that I want to send

Yes, it is a standard ST function.I tried to step in this function and probably the DR register do not get the data that I want to send