When I set it in Branding → Universal Login → Customization → Widget → Logo url, I briefly see a flash of yellow as it loads, but then shows a broken icon in the preview photo. The login page spins and times out, but if I reload the page I get the default Auth0 icon. (It was two blue squares before I began.)
Cleared the cache and cookies, closed/re-opened the browser, same thing.
I went to your login page and see some interesting behavior. Sometimes I see the Auth0 logo, and when I refresh sometimes it doesn’t change and then sometimes it does change to the broken logo. Watching the network traffic when the broken logo appears shows a 403.
Can you try removing the logo_uri from the client and just have the logo_url set under the Branding > Universal Login settings? Or vice versa - essentially, I want to see if only having one set resolves the issue.