Are you using a Win 10 PC with the final SFP-11 build? (345 I think). Cold boot the PC and try again Try another audio device type like 'Ms Sound Mapper' or 'Classic Wave Driver' in the "Options> Preferences> Audio" menu. Does this happen on all file types? Try a PCM <.wav> file.
btw, welcome to the Magix Sound Forge users forum @Bruno-Toussaint.