Kindly follow the steps below to re-set permission for the OTG drive.
(1) Unplug the OTG from your smart phone.
(2) Press the Recent Apps button, and close the Transcend Elite app running in the background.
(3) Restart the Transcend Elite app.
(4) Plug in the OTG drive.
(5) As demonstrated in the image, select the OTG drive for which you would like to re-authorize permission.