i have the same problem with pfsense 2.5.x and ntopng 0.8.13_3
it's still trying to download geoip from the wrong url
$fetchcmd = "/usr/bin/fetch";
$geolite_city = "https://geolite.maxmind.com/download/geoip/database/GeoLiteCity.dat.gz";
$geolite_city_v6 = "https://geolite.maxmind.com/download/geoip/database/GeoLiteCityv6-beta/GeoLiteCityv6.dat.gz";
$geoip_asnum = "https://download.maxmind.com/download/geoip/database/asnum/GeoIPASNum.dat.gz";
$geoip_asnum_v6 = "https://download.maxmind.com/download/geoip/database/asnum/GeoIPASNumv6.dat.gz";
i have changed it inside /usr/local/pkg/ntopng.inc as suggested here -> https://redmine.pfsense.org/issues/9211 by Mark Vejvoda to
$geolite_city = "https://centminmod.com/centminmodparts/geoip-legacy/GeoLiteCity.dat.gz";
$geolite_city_v6 = "https://centminmod.com/centminmodparts/geoip-legacy/GeoLiteCityv6.dat.gz";
$geoip_asnum = "https://centminmod.com/centminmodparts/geoip-legacy/GeoIPASNum.dat.gz";
$geoip_asnum_v6 = "https://centminmod.com/centminmodparts/geoip-legacy/GeoIPASNumv6.dat.gz";