Pin Lock quick connect reassembly

Hello from Ontario, and Help.
I've been lurking and absorbing info from you all for a while.
I now have a question I can't find addressed previously.
I've taken my gas connector apart to clean. Now have re-assembled but,
it won't compress and retract to go on post.
I then took apart another quick connector to compare assembly, seems the same, and now this connector doesn't go on correctly either.
I've tried several kegs. No luck.
Help Please.
Dave.

Maybe a dumb question but, did you try reversing the position of the pin inside the mechanism?

Thanks for pointing me there. It seemed so obvious that I was thinking you were being sarcastic. BUT you were right... with the second coupler( it is slight different design - plastic vs. metal ).
The origional steel coupler is still not cooperating. It seems that the pin that pushes down on the post, will not retract far enough back into the coupler in order for the coupler to lock onto the keg post.
Any ideas would be appreciated.
Thanks, Dave.

For this I'd be looking at the spring for any signs of a kink or looking at how far the end cap is seated. I've only got the plastic couplers.