Which version of DLP? You would not need the WCF service unless you have some really old agents running out there.
Also, enter the override password again (different places in ePO/DLP depending on the version) and save it - do a wakeup call and try again.
Thanks Chris. It started to work again, after i played a bit reinstalling extensions, who knows why...
I was now going to upgrade ePO server to 5.9 but seems that there is not any DLP agent version 10 available...so i guess the well known issue with DLP and Chrome v58 cannot be fixed at the moment...
What ended up working? I am trying to make a DLP11 USB blocking bypass code for the first time and getting "Failed to generate the selected key: "