when I set automatic cleaning schedule it display this error
and the link to customer support redirect me to 404 error page
please advice me what to do
I can't replicate that error,
Can you give a few more details please.
Are you logged into Windows as an Administrator or as a Standard user?
What are you trying to set, is it Cleaning reminders or Automatic cleaning?
Are you using an Antivirus other than Windows Defender, if so which one and what version number is it?
The first thing I'd try is to reinstall CCleaner, just in case it didn't install properly.
Don't uninstall the one you have now; that way the new install will pick up your licence key.
Download the 'Slim' installer (3rd one down) from here: <a href="https://www.ccleaner.com/ccleaner/builds" ipsnoembed="true" rel="external">https://www.ccleaner.com/ccleaner/builds</a>
Double click the downloaded ccsetup608_slim.exe to reinstall CCleaner.
When on the last screen it asks if you want to open CCleaner leave it ticked and click Finish.
Check if you can set a schedule now.
(PS. I know this screenshot is 6.07 but it's just the same for 6.08).