Hello need some help  please.

My AX73 is in access point mode, connected to optic-fibre modem KPN , int eh pas i had 1 USB external hd shared on AX73 , no problems so far .Working perfectly, sharing ,read/write all ok.Now ik connected a usb hub to extend my USB HD external with 2 WD Mybooks.

So then the problems occur, reading is  possible, but writing give an access error code 0x80070032 no creation possible, request not supported

Any suggestions