Xnconvert failed to rename files as date

I got some photos and want to rename as date, such as "2023-12-25_17-59-53", I used Xnconvert to do that according to the Exif info and that worked, I successfully renamed thousand of them on a memory card, but all of a sudden that no longer works, even I select one file to rename but it does nothing, what would be the cause of that ?