The steps you have posted do not seem relevant to the problem. You have problems with opening the error Excel file, right? So how are you doing THAT? Is the file generated on the server? Are you downloading the file using WinSCP?

(I used WinSCP to upload songs to the server)
1. First I make data entry at the excel file for the title of the song, name of the artist, audio type, etc.
2. Next I put the excel files, images, and songs in one folder.
3. lastly I drag the folder from left to right in order to upload the song to the server.
4. If mistakenly I made some error at the excel entry then it generates the error excel file which tells us that we made an error in the particular entry.
5. [b]the error can be only known if we can open that particular error excel files and we can rectify and reupload successfully.
The thing is that when we open that error file it tells us that(Excel can not open the file $130821.xlsx because the file format or extension is not valid. Verify that the file has not been corrupted and that the file extension matches the format of the file.

Sorry, I do not understand. Please provide step-by-step instructions for reproducing the problem. What does it mean "file generated from WinSCP during the file transfer".

Error Excel file generated from WinSCP during the file transfer could not get open. Those Excel files are generated when we made an error in the entry as per the database. Before it could get easily open but now shows the message that

excels can not open the file $130821.xlsx because the file format or extension is not valid. Verify that the file has not been corrupted and that the file extension matches the format of the file.

Please help as tried different ways but still couldn't.