Error being thrown out on server logs

Hi, I am noticing that I am getting an error thrown out on the server logs that shows this:
file_put_contents(ssh2.sftp:///home/sitefolder/public_html/wp-content/uploads/generateblocks/style-3573.css):failed to open stream: operation failed

I have checked and I do see the folder path there but am unsure what else to look for or do at this point.