hylianhero27
My guess is you have a strap pin at the base of the guitar but not up at the shoulder. Mine is the same and it's a L'arrivee. you can do one of a few things:
1 - Use a string to tie the headstock (just under the strings on the headstock) to the free end of the strap
2 - Have a professional install a strap pin on the shoulder
3 - Use Super-glue.
(Option 3 is to be used at player's risk; results may vary)
instead of super glue, I personally just took the old strap... pins? (I guess they would be called?) from my Epiphone (Straplock replacements) and screwed right into my classical guitar with them.

Don't worry, I payed more for the Ernie Ball Black and Silvers then the guitar itself.
And that grime is left over from the duct tape I was using to hold the strap on. (Yeah, I don't really care what it looks like it's $5 guitar)