Your middle picture shows the plastic protector is still on the optical cable. Remove the protector as mentioned in post 2. The TV output picture is not very clear and is quite small. Can you get one that's clearer if the protector removal doesn't solve the problem?
I'm assuming that you know that the cable needs to be "parallel" to the back of the TV and not perpendicular to the back of the TV, and that there's only one way it fits - there's a flat side and the other 3 sides.
Once it's inserted properly, you should see a red light coming out the other end that goes into the AVR. Also, you'll need to typically turn off the internal TV speakers in the TV audio setup menu to enable the optical output.
I made the same mistake at first. It's obvious to those who have previously worked with S/PDIF that the protective cover on the connector needed to be removed. There is also a S/PDIF mini-plug that requires a different cable or adapter.