PHP7 not working but other model does

my web page with php on it ssays BAD GATE WAY
and heres the log

Jan 17 21:22:48 2019 daemon.err uhttpd[13197]: Error relocating /usr/bin/php-cgi: explicit_bzero: symbol not found
Thu Jan 17 21:22:48 2019 daemon.err uhttpd[13197]: Error relocating /usr/bin/php-cgi: fopencookie: symbol not found
Thu Jan 17 21:22:48 2019 daemon.err uhttpd[13197]: Error relocating /usr/bin/php-cgi: explicit_bzero: symbol not found
Thu Jan 17 21:22:48 2019 daemon.err uhttpd[13197]: Error relocating /usr/bin/php-cgi: fopencookie: symbol not found
Thu Jan 17 21:22:48 2019 daemon.err uhttpd[13197]: Error relocating /usr/bin/php-cgi: explicit_bzero: symbol not found
Thu Jan 17 21:22:48 2019 daemon.err uhttpd[13197]: Error relocating /usr/bin/php-cgi: fopencookie: symbol not found
Thu Jan 17 21:22:48 2019 daemon.err uhttpd[13197]: Error relocating /usr/bin/php-cgi: explicit_bzero: symbol not found
Thu Jan 17 21:22:48 2019 daemon.err uhttpd[13197]: Error relocating /usr/bin/php-cgi: fopencookie: symbol not found

How did you install PHP?

opkg install php7-fastcgi then add these line in utthp list interpreter ".php=/usr/bin/php-cgi"
then httpd restart realy need help badly....

You need to upgrade your system to have a newer musl libc.

dunno how im using xiaomi mi router 3 with openwrt on it