Not familiar with your machine. For the write protection as a general idea, there is often a switch or cover that needs to be moved for the "deactivate write-protection" part. This article may help -- but does not explain the dreaded "but it worked before and doesn't now" problem.
https://www.usbmemorydirect.com/blog...ion-usb-drive/
On a friend's Brother Embroidery machine we had a somewhat similar problem -- the standard modern flash drive was too large to be read by the sewing machine -- ah, the speed of computer power and obsolescence. We had to buy a set of lower capacity flash drives, which were fortunately cheap and distinctive in appearance. She could still transfer from her laptop to the lower capacity drives and then to the machine.