Well this could be anything. Why are you on 6.7? The current version is 6.12. If you want assistance then you must open a Support Request. The version you are on is 3.5 years old.
Personally, I would upgrade to 6.9 then to 6.12. The only reason for staying on 6.7 is if you continue to use the Windows Client. Since it does not support Workflow Manager what is the use case here?
Senior Director Support Americas