If you were having a server/DB connection issue you should see problems with EPO in general and not only with DLP. It sounds more like your client systems are not communicating with EPO to get the policy update. You can verify by checking the policy revision ID of your policy on the EPO server and the policy revision ID that the client system has. You can find this by selecting the system in the system tree and going to the products tab and selecting DLP. Towards the bottom of the page under the 'DLP Policy' section it will state the policy revision ID that the system has reported the system is currently using to EPO. Also ensure that the last communication timestamp on the client systems are updating.