So I've been trying to make a new spell, but it isn't allowing me to specify a duration or range for the spell. I've tried reloading the page and accessing form a different device to no avail. I have it specified as concentration, but it won't let me enter how long it normally lasts.

Have you tried changing the duration type to see if it let's you edit duration time.

Yes, I've tried it on every option but it never let's me edit the time.

I would recommend posting a link to the homebrew spell so that a mod can take a look at it.