Canon 17-40mm f4l Can't attach in camera

[lelmota]

Hello!

I have a Canon 7D and used the Canon Lens 17-40mm f4L every day. This lens never fell or was hit. There is no visible why the lens has stopped snapping into the camera. It's like there's something blocking the fit. I can use other lenses in 7D as usual. I wonder if anyone has gone trough something similar and has managed to solve this problem; Thanks!

[jrhoffman75]

Look for a piece of debris perhaps stuck in the depression that the locking pin snaps in.

[CaliforniaDream]

Also verify that all of the screws are tight.

[jrhoffman75]

I forgot to mention - also verify that the lens lock button on the camera moves freely and isn’t sticking. 

[ebiggs1]

"...also verify that the lens lock button on the camera moves freely and isn’t sticking."

Hmmm, doesn't sound likely does it?  

"I can use other lenses in 7D as usual"