How to fix: HORDE ERROR : 500 NO RESPONSE FROM SUBPROCESS WITH EXIT SIGNAL: 0

[sajugovind]

You need to check if the server is having custom mysql version? Like below?

root@server2 [~]# mysql –version
mysql Ver 14.16 Distrib 5.2.12-MariaDB, for unknown-linux-gnu (x86_64) using readline 5.1

This custom version of MySQL conflicts with the internal cPanel PHP, so I disabled the “usecpphp” file so that Horde could send email properly:
root@server2 [~]#

in that case you need to do

root@server2 [~]# mv /var/cpanel/usecpphp /var/cpanel/usecpphp-disabled

Thank you,