Thanks for all solution here. I tried most of them but none worked for my case. in My case, forum is sending all notification for Forum and News Forum.
BUT for SITE NEWS no email are sending to any user and server error log showing this error repeatedly.
[17-Oct-2016 09:30:00 America/Los_Angeles] Default exception handler: Can not read file, either file does not exist or there are permission problems Debug: [dataroot]/filedir/26/90/269002a05f5ba287d8f75989ad8b54c93a0173f4
Error code: storedfilecannotread
* line 445 of \lib\filestorage\stored_file.php: file_exception thrown
* line 1967 of \lib\filelib.php: call to stored_file->readfile()
* line 2333 of \lib\filelib.php: call to readfile_accel()
* line 4041 of \lib\filelib.php: call to send_stored_file()
* line 37 of \pluginfile.php: call to file_pluginfile()
[17-Oct-2016 09:37:13 America/Los_Angeles] Default exception handler: Can not read file, either file does not exist or there are permission problems Debug: [dataroot]/filedir/26/90/269002a05f5ba287d8f75989ad8b54c93a0173f4
Error code: storedfilecannotread
* line 445 of \lib\filestorage\stored_file.php: file_exception thrown
* line 1967 of \lib\filelib.php: call to stored_file->readfile()
* line 2333 of \lib\filelib.php: call to readfile_accel()
* line 4041 of \lib\filelib.php: call to send_stored_file()
* line 37 of \pluginfile.php: call to file_pluginfile()
any help Please?