Unable to homebrew campaign

I am the DM and I'm attempting to add a homebrew spell to the players. However, no matter what I do, the option isn't appearing. I've ensured the homebrew option is selected for each of them, but nothing has changed. Likewise, with my own created characters, I couldn't apply the spell unless I created a new character. In an attempt to get the homebrew working in the campaign, I had one of my players create a test character, and despite being a new character, it wouldn't allow me to add the homebrew spell.

That is exactly what I did. Thank you I wasted so much time trying to figure that out.