Disco Lazio Permesso upload problem

this week i applied for permesso (note that my appointment for fingerprints is in May 2025!) so i tried to upload permesso receipt on my account of Disco Lazio to unblock area for scholarship. But when i upload the document and reload the page - it is all blank as if i didn't upload anything? Can you please help to solve this problem. I am very confused and stressed over this situation.