Why aren't my updates publishing to the server despite them showing in the preview?

Can you confirm the time and date stamps on remote server files are what they should be?  See screenshot.

If you're happy to share a screenshot do this:

1) connect to your remote in dreamweaver

2) expand the file menu, take a screenshot and post it here

A common mistake is uploading files to the wrong remote folder - On your remote there should be a web root folder. Commonly used names for web root folder are public_html or htdocs.

• Try using a different browser. 
• Try using a dedicated FTP client like Filezilla to upload files.
• If you still can't see new content online, check to be sure you're uploading to the correct server and root directory. 
• Or contact your hosting provider.  Maybe your host changed something on their end.

You are not giving us much to go on, like version of Dreamweaver, Dreamweaver site settings, your O/S and your actions leading up to the problem.

At this stage I can only assume that a browser cache is causing the problem. To clear the cache on my machine, I use CTRL+SHIFT+DEL and follow the prompts.