We can't diagnose problems like this based on no information: it sounds like you are trying to read a client Excel file on your server - because C# code runs on the server, not the client - and you can't do that. You would have to upload the file to the server, process it (I'd suggest using something like
NuGet Gallery | ExcelDataReader 3.6.0[
^]) and then store the data you read from it into your DB.
But we can;t give you more detailed instructions: Remember that we can't see your screen, access your HDD, or read your mind - we only get exactly what you type to work with.