No Congratulations screen when publishing

Hello all, has anyone come across this issue before.

I have a large (circa 760 page) guide that I am publishing.  As I have worked through it  have published with no issues.  The final section was recently added and when I tried to publish it ran through the process as usual but didn't display the congratulations screen.  Instead it just returned to the normal screen.  I have tried on several occasions, I have tried at different locations in case it was a connection or upload speed issue.  I have just tried again on a different laptop AND changing the name and therefore creating a new course and I have the same result.  Any ideas?  Is there a size limit for Articulate online?

Many Thanks

Nick