Error message

Warning: readfile(https://poc.solverlabs.com/sites/default/files/Screenshot_2017-08-06-18-23-15_1.png): failed to open stream: HTTP request failed! HTTP/1.1 404 Not Found in poc_common_download_file() (line 426 of /var/www/poc.solverlabs.com/data/sites/all/modules/custom/poc_common/poc_common.module).