Changing DNS but Save button greyed out.

[lifesgoodx3]

Hi everybody! Thought I would join the club as I recently got my LG G3. I am having one very, very frustrating situation that I'm hoping someone can help me out with. On my previous cell phones (Samsung S3 and Motorola Moto G) I had no problem changing the DNS settings as I want to watch Netflix et al from other countries. For some reason, and I have searched endlessly on every forum regarding greyed out save buttons, I cannot find an answer to have the DNS saved. As soon as I long press on Wi-fi the save button is greyed out and no way no how can I change that. Please tell me what I am doing wrong! Thanks!