Anywone know why my SanDisk would be giving me this message? Connectint to Apple iOS.Thanks

Hi, thank you for reaching out. Can you please try to use a different PC to see if you still receive the exact error message on a different computer. Please keep us posted. Thank you!

If not already formatted, format or reformat. Also, what are the card's specifications?

Formatting memory card can depend of the device where they were formatted on. To be sure that the card can be used to record your pictures by your camera (drone), always format it on the camera.
But it is not sure all devices can read your memory card. Try it on another device or try using an external card reader.

Am I correct in assuming that you are actually asking about reading a card on your computer AFTER having flown and recorded? If that is the case there could be several issues:
1)If you turn off the aircraft before stopping a video recoding session, I have seen corrupted cards.
2)The actual SD card could be bad for a variety of reasons (bent taking it out, static discharge or just plain product failure)
3)The SD card you are using is not supported if it is over 64 and/or 128 depending on the aircraft.

There are programs that can recover SD cards if they are actually operational. More on that if you need it.