CD player not working anymore
 

Hello,
I'm new to this forum and I have a problem with the CD player on my Mini Cooper S.
The CD player does not work anymore. Radio works fine, but when I press the MODE button to switch to CD mode, the display just shows "TR". There is no CD inside, but I cannot insert a CD, it seems to be blocked. The eject button does not do anything.
Does anybody know what the problem might be? Is there a way to "reset" the CD player?
Thank you!

What year ???

2003.
I believe that the last time I ejected the CD, something bad happened. There is a "CD" writing on the display, which I think is shown when there is a CD inside the player (even though right now there's no CD). I think the player believes it has a CD inside (so it doesn't let me insert one in), but when I press the eject button, it does nothing (probably because the hardware doesn't detect the presence of a CD).