There is currently a known issue with the HP Smart (formerly HP ePrint) app which means that PDFs which include a level of encryption are unable to be printed using the app.
LPC Buddy PDFs include some very low level encryption as a means of protecting our IP rights. Unfortunately we are unable to turn this off, however this should not normally affect your ability to read or use the document as you would any other PDF file. We do not restrict the ability to print our PDFs.
If you are struggling to print with HP Smart, the current known workaround is to print by bypassing this app. If you are on a computer, this will normally require you to download and install the full print driver for your printer available from here: https://support.hp.com/gb-en/drivers.
If you are on a mobile device, you will need to print your PDF using one of many available third party printing apps which you can download from the App Store / Play Store.