This is probably unhelpful because I’ve been having a plethora of problems with X9 the past few weeks and support keeps wanting to set up a remote session. How about you fix your software and stay out of my computer?
But, I had this problem and I was able to fix it by: checking my instant formatting, checking my output style and checking my reference type (some reference types aren’t supported by my output (APA 7)).
Hopefully it’s working again for you though.