First, please make sure that you are attempting to upload one of the supported file types (see What file types or formats can I upload?). If your file is supported, please try again using a different browser (e.g., Firefox or Chrome instead of Internet Explorer). This should resolve the issue in most cases. If you continue to have problems, you may need to try using a different computer or try from a different network (such as at home instead of at school).
Please also watch our QuestTips video for some helpful tips on uploading materials.