Hi Crystal,
Please try updating to the latest version and see if the issue still persists. Version 6.10 is very old and it is likely that the old version is what is causing the issue.
Latest official: https://dev.apryse.com
Release channel: PDFTron Systems Inc. | Nightly
Developer channel: PDFTron Systems Inc. | Nightly
Latest official builds, and Release channel, are ready for production usage, however the developer channel builds do not get the same amount of testing and can be in a state of change.