Portal not working

I can't get to the nether using the portal. The portal looks normal, but when I step into the purple sparkling area I don't go to the nether, I just pass through to the other side.  I've tried breaking it up and making a new portal in a different location, with the same results.  I took out all my mods and still couldn't get to the nether.  If you need anything from me, let me know.