Did you click the 'share' link on the left (which generates a public URL for a snapshot of the chat), or did you just copy the URL from the address bar (which will only work for you)?
The shareable URLs contain the word 'share' in the path.
https://chat.openai.com/share/b8f06d5e-f2d9-47d7-9c60-69b088...
AH... I fd up and apprently copied the URL...
EDIT,
You may link this link as well
https://chat.openai.com/share/0e2d652e-09a6-4cba-a766-dcf2c6...