Does it do this with all your tapes? If it only one it sugests that the tape is getting tight and the machine interprets this tightness as meaning that the end of the tape has been reached, so it spits it out. If this is what is happening the machine will still FF and RW ok as these go much faster than playing, so can overcome some stiffness in the cassette.
sorry should have stated all cassettes .i have fast forwarded and then rewinded the tape, then tried to play,but it plays for a couple of seconds then ejects.