You will not be able to upload files if your account is running out of free disk space or you have reached your inodes limit. Always check via your control panel that you have enough free disk space to upload your files.
Why can’t I upload files?
Working in the web hosting industry for over 13 years, Rado has inevitably got some insight into the industry. A digital marketer by education, Rado is always putting himself in the client's shoes, trying to see what's best for THEM first. A man of the fine detail, you can often find him spending 10+ minutes wondering over a missing comma or slightly skewed design.