File_get_contents fails to open file

yes, Here is the code:

 $path = __DIR__."/uploads/".$user_id.$_SESSION['upload_time'].".html";
file_get_contents($path, "r+") or die("Unable to open file!");

Here is a screenshot of thr error message:

I noticed that all slashes in the path are backslashes except for the ones of the uploads folder.
Could this be the problem ?