Document disappeared from account when saved as PDF

I have just used the Adobe scan app on my iphone to scan 450 pages of a document. I then clicked "save as PDF" and it said "saving" for a few minutes. After this, that screen dissapeared and it took my back to my other scans but that scan was not there. 

I have looked online and on my account but cannot find this scan. It took me nearly 3 hours to scan the document and I'm really frustrated that it seems to have just completely dissapeared.

I am signed in on the correct account as I scanned another document and saved it in the same way as a test and it saved and was on the account straight away. 

If anyone could please provide any help with this it would be really really appreciated. Thank you.