Nearly always it's one of three things. They haven't accepted the invite, they're signed in with a different email than the one you invited, or they only have Viewer access. Editing needs all three: an accepted invite, the exact invited email, and Contributor or Full Access.
Check these in order
Did they accept the invite? Editing starts only once they open the invitation and accept it. A pending invite grants nothing.
Are they using the exact email you invited? Access is tied to that one address. If they sign in with a different Google, Facebook, or magic-link email, Wishpicks won't match them to the invite. Re-invite the email they actually sign in with.
Are they signed in at all? A logged-out visitor can only view.
What level did they get? A Viewer can never edit. Re-invite them as Contributor or Full Access.
Are they trying to change someone else's wish? A Contributor can only edit or remove the wishes they added. Full Access lets them manage all of them.
Are they trying to rename or delete the list? Only the Owner and people with Full Access can do that.
Good to know
Making the wishlist private won't fix editing. Visibility and edit access are separate things, and only an accepted email invite grants editing rights.
If the invitation never arrived, ask them to check spam and confirm you typed the right address. You can send it again: open their entry in your access list and choose Resend invitation. Invites don't expire, so an old one is still valid and there's no need to start over. If a resend won't go through, that's the guard against invite spam. Wait a few minutes and try once more.
Someone new to Wishpicks can sign in with Google, Facebook, or an emailed magic link using the invited email, then accept.
Still stuck? Contact support and we'll take a look. We reply on business days.
Related
"How do I invite another person to edit my wishlist?"