Do not type into that empty form. The message means the editor could not find that publication on the account you are signed in with, and the blank fields are not a new publication waiting to be filled in. Anything you enter is aimed at a publication that is not yours, so it fails on save and is never stored.
Leave the page and open the publication from your own list instead.
Why it happens
The editor only ever serves publications you wrote. Anything else comes back as not found, which the page reports as a failure to load rather than as a permission problem.
- The link belongs to someone else. An editor link cannot be shared. Sent to a colleague it gives them this, not your draft.
- You are signed in with a different account. Check the name at the top right against the account that created the publication.
- The publication has been deleted. It cannot be reopened from here.
Reloading does not help in any of those three cases, because the request that failed will fail again in exactly the same way.
What to do instead
Open Profile, then Publications in the left sidebar. Everything listed there is yours, and every item on it opens. Drafts and published publications are both in that list.
If you are signed out
You are sent to sign in and returned afterwards. Occasionally you will land on the publications home with a notice reading "Please log in to create a publication" instead, which happens when the page loaded before your session did. Sign in and open the publication again from your Publications list.
Sharing a publication for someone to read
Send the published address, the one with your publication's name in it, not the editor address. A publication that has never been published has no public address to send.