What note ID did you try?
Discussion
what browser did you try it on? it worked for me on chrome.
this is the note id that i used
note175gky5hnw0xg6678j4hk00ragccac2vz0m5juhldq2akgc6rx6nslxapwp
I used this exact note id and got this 
The note might not be on many relays. Currently, I’m only checking some of the main relays for the note unless you use an nevent which includes relay hints. You can create an nevent with relay hints using https://nak.nostr.com. I’ll work on making it smarter by checking the author’s write relays. It will make the app a little slower though.
I used a normal note ID it didn't work it says couldn't find note