Turn the phone off. Remove the SD card. Turn the phone on. Go to Settings/General/Date and Time and make sure the date, time and timezone are on automatic. If the date and time are correct after a few minutes (or it may take a restart), the SD card does need either reformatting or replacement. (If it's a SanDisk card, go to
SanDisk Online RMA Request and fill out a request for a replacement if formatting doesn't fix it. If it's not a SanDisk and formatting doesn't fix it you can still try to get it replaced, but, depending on the manufacturer, it may be anywhere from a little more difficult to next to impossible.)