Symptoms
After upgrading to 5.4.14, webmail stops working. This message is shown after a successful login:
"This page was disabled by security reason. You can log into webmail using POA CP or url like 'webmail.yourdomain'."
All tests from KB article #6602 are successful.
Cause
Horde requires the PHP4 module to run but, after the upgrade, PHP5 is added to the pem httpd config:
~# cat /usr/local/pem/etc/apache/httpd.conf_pem.phpmodule
LOADMODULE php5_module modules/libphp5.so
Resolution
Check that PHP4 is installed:
~# rpm -qa | egrep "php4-4.4.9-7.pem|php53-5.3.3"
php53-5.3.3-13.el4.pem
php4-4.4.9-7.pem
Change the pem httpd config so that it uses the PHP4 module:
~# cat /usr/local/pem/etc/apache/httpd.conf_pem.phpmodule
LOADMODULE php4_module modules/libphp4.so
It may be necessary to configure the specific Apache configuration as described in the Resolution part of KB article #116089. This ensures changes persist through reboots of the node.