Not knowing what your uploading, how your uploading it, or where it's uploading to, the generic answer is the simple action of uploading a file does not by itself set the permissions.
Normally, permissions are set on the destination directory/folder and the stored file will inherit those permissions, i.e. owner can read/write and others read only. Once the file is stored, you can change the permissions if your remote access method/tool/app allows changes.
Now, you could have uploaded a file with a different name than what the server application is looking for. Example: You uploaded file.htm and your web page HTML code is looking for file.html