Both answers are answered at almost same time with the difference of 4 minutes.
Quoting directly from Missing edit link?
There are many options here:
- You are not logged on and the post is 10 minutes old or less
- There is already a pending edit on this post
- The queue is full, only happens rarely on new SE sites with no moderators
- You have been banned for a week cause you submitted many rejected edits
Options 2, 3 and 4 only apply if you have less than 2,000 reputation.