Hello Pallavi,
Can you place the file again and try to view the message in your channel monitoring? Can you check if you are able to view the message there?
If yes, then it must be available in Message monitoring too. Also please ensure, this is the only channel which is accessing the folder. You can confirm it by archiving the file once picked. This will confirm, this is the channel which is picking up the file.
Regards,
Nitin