I have USB memory connected to BE6500 router. I can see the disk on USB share display and addresses for SMB, local FTP and Internet FTP, all are active. Whole drive is shared. Have secure share on and users for read&write as well as read only. But when I try to connect the drive from Windows, I can see the drive and directories in it, but cant create new directories and neither add new files, even when using read&write user. I can delete existing files. Additionally if I try to open any file on the disk (regardless is it a pdf file or a picture file), it opens browser page, not the file. I have tried FAT32 & NTFS and exFAT file systems on the disk, no difference. 

I would like to use the disk to save  surveillance camera videos, but also camera application says that it hs no permission to write on the disk.