I had the same problem.
type the command:
cat /usr/local/etc/pkg/repos/pfSense.conf
the file should read as below:
FreeBSD: { enabled: no }
pfSense-core: {
url: "pkg+http://pkg.pfsense.org/pfSense_v2_3_1_i386-core",
mirror_type: "srv",
signature_type: "fingerprints",
fingerprints: "/usr/local/share/pfSense/keys/pkg",
enabled: yes
}
pfSense: {
url: "pkg+http://pkg.pfsense.org/pfSense_v2_3_1_i386-pfSense_v2_3_1",
mirror_type: "srv",
signature_type: "fingerprints",
fingerprints: "/usr/local/share/pfSense/keys/pkg",
enabled: yes
}
if you find it to have https as below:
url: "pkg+https://pkg.pfsense.org/pfSense_v2_3_1_i386-core",
change all ocurrences of https to http editing the file with vi
save it and try installing the packages again.