Unknown error has occurred failed to play video

[Ghstrdr_22]

I have a 1TB MICRO SD CARD AND MY PHONE IS N
OT SAVING PHOTOS AND VIDEOS, IS THERE A FIX FOR THIS CAN ANYONE HELP ME? 

[patriciostarr]

Make sure your videos were damaged. It looks like your videos were dammadge

[0m3n]

what brand was the micro SD card? you can try to unmount/eject the SD card then plug it back in. you should never just pull it out. ALWAYS unmount.
settings/device care/storage/SD/ click unmount button

[realaud]

It is not unheard of for an SD card to be defective out of the packaging. The card could also be very slightly misaligned in the tray - not enough to get a "no SD card" error, but enough to corrupt photos/videos. Is this just happening with videos, or with photos as well? I would take the advice of unmounting the SD card, removing it, cleaning it (perhaps trying it in card reader on another device), remounting it and rebooting your device. You only have to use the unmount command if you are trying to do it while the phone is on. If you shut the phone down, you can just open the tray and reseat the card. It may not help with recovery of what is already on there. Also, check to see if your videos were backed up to Google photos - that setting is on by default unless you turned it off or ran out of space - if they are in Google, you wouldn't lose anything if the SD card proves to be defective.