I'm having the same problem, but for all my blog posts (pages are fine).
Have turned off all the plugins and tried another browser to see if is browser cache, problem still there. I'll go through:
- it could be permalinks issue...
- check for .htaccess file presence and check if the default wordpress mod-rewrite code is there or not. There are times when .htaccess file is not writeable or gotten deleted
- Checking the server error log for your hosting account. Ask your hosting provider for assistance to locate them.
Not sure how to check for the following:
- it could be configuration issue
- it could be memory issue
- it could be optimization issue
Am on a shared server.
Will watch this thread with interest, and report back if I figure it out.