There are many answers to that question the most likely are:
1/ The rule is misconfigured - please describe how you have set the rule up.
2/ You are testing with a short document that just contains the word 'classified' once or repeated. You need to have a page of non repeating text plus the keyword to trigger the rule. hint: in Word enter =RAND(20) then [return] to produce sample text.
finally you can use the DLP Diagnostic Tool (from the Product Downloads area) to check the document against the policy/rules. Look under the 'Tools' tab.
thank you for your response
1 - the rule set up :
in dlp policy manger --> action-->new rule set --> in rule set do action --> new rule --> clipboard protection
Clipboard Protection Rule Name: State: Severity: Enforce On:
Below the screenshot for DLP Diagnostic tools
the problem is resolved
by default DLP Content protection is disabled in policy Default Windows Client Configuration policy --> operation mode and modules
we must choose Device Control and full content protection to enable Device Content Protection and Device Control
thank you for your collaboration