I am trying to make a picture into a line drawing like a colouring book but it keeps saying Prompt declined One or more words may not meet User Guidelines. Try changing your prompt. I have never had a problem bofore using these words

I am an embroidery digitizer and I use firefly to make my designs then I ask it to make it into a line drawing but when I put the picture up to make it into a line drawing I get (

Prompt declined

One or more words may not meet User Guidelines. Try changing your prompt.) 

These are just animals eg cats and dogs-  I have never had an issue before making picutres into lines like a colouring book.