If you are unable to upload a file to the Virtual Classroom, you are either uploading a file which is not supported or its size exceeds the permissible file size allowed on WizIQ. You also need to ensure that your internet connection is working fine. It is required for uploading a file successfully.
You can only upload files that are supported in the Virtual Classroom. Moreover, the files uploaded by you should be of the permissible size.
To know about the supported file formats and permissible file sizes, read What file types are supported in the Virtual Classroom?