Hi @evanlei1
IMO normally this kind of “no brand” SD card product lifespan is quite short (limited write lifespan)
I had threw away alot of those “gift” sd cards due to card error.
Test with another known working memory card to see if it works.
if there are important data, you might need to send in to professional service for recovery. (Note: It does not come cheap)
What is your model of your panasonic camera?
check on the product specs of what size and sd card it is supported..
some reputable brands, e.g. samsung, kingston, lexar, sandisk you can consider for replacement.