If the error appears with several different SD cards, the problem is more likely in the camera’s card slot or electronics than in the cards themselves. In this case, the cause turned out to be moisture: the camera had been exposed to light rain, and water likely affected the SD-card slot.

Cleaning the SD slot area and contacts, then letting it dry thoroughly, resolved the intermittent “Card cannot be accessed” message.

So if you see this behavior after using the camera in damp conditions, check for moisture contamination around the card slot and let the camera dry completely before use. If the issue returns, the slot may have corrosion or damage and should be professionally serviced when possible.