не мог декодировать Base64 Облачный

I had encountered the same issue . Just send the bas64 file as json and not as formData . step 1 : app.use(express.json({ limit: "50mb" })); app.use(express.urlencoded({ limit: "50mb", extended: true }));

step 2 : since you are converting the image on onChange event the file is converted to base64 . so just send that data as json .
Lol!