Facebook spiders have to find your new page before it will let you share it.
This normally takes about 24-72 hours from when you make your listing live.
During that period if you try to like or share you will get a message “Page not found”, but you can still share your profile by copying your web address and pasting into a Facebook post.
If you have activated more than 72 hours ago and still have the “page not found” message, please get in touch.