Does it hang on a specific page? What is on that page?
Do you export to a standard like X-4?
N. I don't believe it does. The process to export literally almost completes and then the "Failed to export" window pops up.
Try the divide and conquer approach.
Export half the doc. Then export the other half.
If one half fails, divide it again and keep doing that until you find the culprit.
what you could try:
1. Save your document with Save As
2. Quit InDesign
3. Restart your computer
Make sure, that no browser like Firefox is working.
4. Try again
Or try a different way of exporting to PDF with a script I wrote some years ago: