Not Synchronize. Locate Missing Folders.
In Lightroom, go the the Folders panel and right click the folders - they should be red if you've moved them in Explorer. The context menu gives you Locate Missing Folders.
If they aren't red, you're getting yourself in a mess. Look at them in Explorer (right click). If the folder is now empty - because you've moved the files - delete the folder and return to the above fix. If it's not empty, check your server has all the files, then delete them.
In future, once images are in the system, make your life easier by using Lightroom, not Explorer, to move folders or files.
John