Collecting Data From A File On Another CPanel Account

I have a problem with a function on my cPanel server where one client is trying to collect informations from a file on another account on same server. And this suddenly stops to work. Once reboot of the server corrected the problem but it is back after just couple of days.

Here are details.
On account www.BLUEaccount.com there is a file index.html and within this file there is a code:

$fcontent= file_get_contents[url];

and the problem is that index.html file on BLUEaccount.com is not loading because it seems can not collect data from data.tmp file from REDaccount.com

But when we take this data.tmp file directly into directory of the index.html file on BLUEaccount, everything work OK.