If you are getting ‘MAINTENANCE’ when tying to click on Horde buttons, it is because you have maintenance turned on. To turn it off. Do the following.
cd /usr/local/cpanel/base/horde/config/
To go the horde config directory.
vim prefs.php
Look for
$_prefs['do_maintenance']
Should be a array variable with some options. Look in the array at the first 2 lines. They should be value, and locked.
Make sure value is set to false and locked is set to true. Then Save, Nothings needs restarting.