MulterError: Unexpected field

i’m sorry, it might be dumb question, but this is my first time error which I can’t solved by searching the solutions on the internet, do you guys mind helping me, what’s going on here, because I’m very new in backend, basically this is about react native courses, when I’m adding the data from UI and push to the backend, this error appear on the backend, I have no clue about this because the code just provided along the courses, so I just use it, here’s the error :

MulterError: Unexpected field
at wrappedFileFilter (/home/ahmadpiee/Desktop/Backend/node_modules/multer/index.js:40:19)
at Busboy. (/home/ahmadpiee/Desktop/Backend/node_modules/multer/lib/make-middleware.js:114:7)
at Busboy.emit (events.js:315:20)
at Busboy.emit (/home/ahmadpiee/Desktop/Backend/node_modules/busboy/lib/main.js:38:33)
at PartStream. (/home/ahmadpiee/Desktop/Backend/node_modules/busboy/lib/types/multipart.js:213:13)
at PartStream.emit (events.js:315:20)
at HeaderParser. (/home/ahmadpiee/Desktop/Backend/node_modules/dicer/lib/Dicer.js:51:16)
at HeaderParser.emit (events.js:315:20)
at HeaderParser._finish (/home/ahmadpiee/Desktop/Backend/node_modules/dicer/lib/HeaderParser.js:68:8)
at SBMH. (/home/ahmadpiee/Desktop/Backend/node_modules/dicer/lib/HeaderParser.js:40:12)