This tickles a bug as reported by Thorsten Marquardt in
https://sourceforge.net/p/davical/mailman/message/58766531/ with this
error message reported:
Exception [0] ldap_get_attributes(): Argument #2 ($entry) must be of
type LDAP\ResultEntry, false given
At line 718 of /usr/share/davical-master/inc/drivers_ldap.php
You need to look in 3da860e5d5e732c2dedb62a73c76608a2b7098a4 for that line
number as I've just made some improvements to the code the last few commits.