Failed to load an application resource (internal error) - error message when previewing pdf in program

Hi,

I keep getting this error message when trying to Preview PDF in program "Failed to load an application resource (internal error)". I haven't changed anything in LiveCycle, so not sure why this is happening. Have had this issue for the past few months. I've been working around it, but it's kind of a pain. Would prefer to view forms in program. Suggestions to fix this?

Thank you!

Stacy