After exporting Excel using NPOI, opening Excel always prompts "unreadable content found". After commenting the relevant code, it is found that it is caused by setting the font of the Excel cell.
There is a paragraph in my code to set the font to "Song Ti": Font.FontName = "Song Ti". After commenting it, export it to Excel and open it, and the previous error message will disappear. I guess it should be to open the fonts that do not support the setting of Chinese, that is, Chinese such as Song Ti and Hei Ti, or because of their own computer. You can set the font to other English named fonts.