Is the MIDI region on the Software Insrtument track muted? or perhaps the track or channel strip itself?
Do you have any channels/tracks soloed?
You can check by opening the Mixer and clicking on the 'ALL' tab.
Thank you for the email.
I have just noticed that I didn't set up grand piano for audio and therefore Logic didn't know what I wanted to do. Perhaps this was the reason. Now everything is working just fine.
This kind of mistake won't happen again : )
Thank you for always being here for us