I just had this problem myself. At first it all worked fine, but I added a new element (PNG image), I then came across this error message when exporting. I found that when I delete the new element, it then worked. I'm no expert, but my advice would be to test removing elements and retry until it works.
A fix, kind of...
I just had this problem myself. At first it all worked fine, but I added a new element (PNG image), I then came across this error message when exporting. I found that when I delete the new element, it then worked. I'm no expert, but my advice would be to test removing elements and retry until it works.