Adobe Express no longer downloading pdfs

Hi there, I've seen some posts about this already, but haven't found a great solution to apply to my particular problem.

I have a couple of document templates in Adobe Express (web version) that (invoices and receipts) that I've been able to download with no issue for about 2 months now. All of a sudden it won't let me download pdf versions at all - it gets to 90% and stops then gives me an error message.

I've tried clearing cache, checking for updates, replacing/removing images etc, but nothing is fixing it.

I just don't know what has suddenly changed to stop me downloading these documents.

They are only 1 page each, so its not an issue of the file being too large.

It seems i can download things as a Jpeg (it still gives me an error, but it does download).

I also tried starting a fresh template, with no changes to it, and it downloaded absolutely fine with no error.  So it seems to be my existing files.  Is there a limit on how many downloads one template can have?? Do i just have to rebuild it and start again?