No such file or directory couldn't create child process

Hello, After I using whmcs to suspend and terminate 3 accounts, all sites run php on my server all encounter 500 Internal Server Error. There are apache error logs: [Mon Aug 24 22:25:14.172591 2015] [mpm_prefork:notice] [pid 1355] AH00171: Graceful restart requested, doing restart [Mon Aug 24 22:25:14.247445 2015] [:notice] [pid 1355] mod_hostinglimits: use Min UID 500 [Mon Aug 24 22:25:14.247476 2015] [:notice] [pid 1355] mod_hostinglimits: use old style for LVE exit [Mon Aug 24 22:25:14.247481 2015] [:notice] [pid 1355] mod_hostinglimits: version 1.0-23. LVE mechanism enabled [Mon Aug 24 22:25:14.247487 2015] [:notice] [pid 1355] mod_hostinglimits: found apr extention version 3 [Mon Aug 24 22:25:14.247494 2015] [:notice] [pid 1355] mod_hostinglimits: apr_lve_environment_init_group_minuid check ok [Mon Aug 24 22:25:15.003586 2015] [:notice] [pid 1355] mod_bw : Memory Allocated 0 bytes (each conf takes 48 bytes) [Mon Aug 24 22:25:15.003618 2015] [:notice] [pid 1355] mod_bw : Version 0.92 - Initialized [0 Confs] [Mon Aug 24 22:25:15.004295 2015] [mpm_prefork:notice] [pid 1355] AH00163: Apache/2.4.12 (Unix) OpenSSL/1.0.1e-fips mod_bwlimited/1.4 configured -- resuming normal operations [Mon Aug 24 22:25:15.004315 2015] [core:notice] [pid 1355] AH00094: Command line: '/usr/local/apache/bin/httpd' [Mon Aug 24 22:26:08.651395 2015] [:error] [pid 116568] (2)No such file or directory: [client 27.245.164.122:5988] couldn't create child process: /opt/suphp/sbin/suphp for /home/username/public_html/room.php, referer: domain.com/room.php?hotelId=1
I did't change any server side setting. Could anyone help me to fix it? Many thanks!!