Can't attach lens

[Carlossavila]

Hey there, I'm having trouble attaching the lens to my Eos Rebel T1, I can align the white squares but when I try to turn to atach it something seems to lock it from twisting, tried forcing a little bit and it does twist but not enough to attach. Some ideas or something I'm missing? Checked both the camera and the lens and there seems to be nothing wrong.

[ebiggs1]

You need to stop and take a step back.  It is obvious you don't know the problem. Neither does anybody here. You are going to cause it to be worse if you proceed.

The mount is damaged what ever the cause. Take it to a pro and have them assess it.

[lelmota]

Hi!

I have the same issue with Canon 17-40mm F4L USM which just started showing this problem and I don't know why and how to fix it. Do you found the reason and resolve this problem? 

(my camera is Canon 7D, others lens still attach normaly in it)

[jemarod]

I have this same issue, but all i did was take it off to put another on and now i can't put it back on to save my life -_-