0 B files / empty files in S3 buket

Hi, I have an application that uploads files to S3 buckets. It all worked fine but now, without any changes to the application, I'm seeing 0 B files on S3 bucket. I'm on a Free Tier and I reached both the 2,000 Requests and 20,000 Requests limits but I do have the payment option enabled so that should not be an issue. Any idea what might be going wrong? Since I was on a Free Tier, is there anything that I need to enable?