Pacman-key --refresh-keys fails: A specified local key could not be updated from a keyserver

Hardware information
$ inxi -Fzc 0
System:    Host: ReemZpire Kernel: 5.2.11-3-CHAKRA x86_64 bits: 64 Desktop: KDE Plasma 5.17.3 Distro: Chakra
Machine:   Type: Laptop System: Acer product: Aspire E5-573 v: V3.72 serial: <filter>
           Mobo: Acer model: ZORO_BH v: Type2 - A01 Board Version serial: <filter> UEFI: Insyde v: 1.25
           date: 07/15/2015
Battery:   ID-1: BAT1 charge: 23.1 Wh condition: 29.5/37.0 Wh (80%)
CPU:       Topology: Dual Core model: Intel Core i5-5257U bits: 64 type: MT MCP L2 cache: 3072 KiB
           Speed: 901 MHz min/max: 500/3100 MHz Core speeds (MHz): 1: 901 2: 911 3: 957 4: 905
Graphics:  Card-1: Intel Iris Graphics 6100 driver: i915 v: kernel
           Display: x11 server: X.Org 1.20.3 driver: intel unloaded: modesetting,vesa resolution: 1366x768~60Hz
           OpenGL: renderer: Mesa DRI Intel Iris 6100 (Broadwell GT3) v: 4.5 Mesa 19.1.8
Audio:     Card-1: Intel Broadwell-U Audio driver: snd_hda_intel
           Card-2: Intel Wildcat Point-LP High Definition Audio driver: snd_hda_intel
           Sound Server: ALSA v: k5.2.11-3-CHAKRA
Network:   Card-1: Realtek RTL8111/8168/8411 PCI Express Gigabit Ethernet driver: r8169
           IF: enp2s0 state: down mac: <filter>
           Card-2: Qualcomm Atheros QCA9377 802.11ac Wireless Network Adapter driver: ath10k_pci
           IF: wlp3s0 state: up mac: <filter>
Drives:    HDD Total Size: 931.51 GiB used: 7.00 GiB (0.8%)
           ID-1: /dev/sda vendor: Seagate model: ST1000LM014-1EJ164 size: 931.51 GiB
Partition: ID-1: / size: 907.42 GiB used: 6.95 GiB (0.8%) fs: ext4 dev: /dev/sda3
           ID-2: swap-1 size: 8.00 GiB used: 0 KiB (0.0%) fs: swap dev: /dev/sda5
Sensors:   System Temperatures: cpu: 49.0 C mobo: N/A
           Fan Speeds (RPM): N/A
Info:      Processes: 156 Uptime: 37m Memory: 7.71 GiB used: 806.3 MiB (10.2%) Shell: bash inxi: 3.0.10
Configuration files and log file

mirrorlist.conf (808 Bytes)
pacman.conf (2.7 KB)
pacman.log (126.0 KB)

Premise

After a successful clean install on an Acer Aspire E5-573 and a successful system update (sudo pacman -Syu), attempting to install additional packages fails on several signature errors: Firefox fails on @tetris4’s key, hplip on @AlmAck’s and the Chakra Build Server’s PGP signatures.

$ sudo pacman -S firefox
resolving dependencies...
looking for conflicting packages...

Packages (15) at-spi2-atk-2.26.0-1  at-spi2-core-2.26.0-2  atk-2.26.0-1  dav1d-0.3.1-1  geoclue-2.5.5-1  gtk-update-icon-cache-3.24.5-1  gtk3-3.24.5-1  libportal-0.0.2-1  mime-types-9-1
              mozilla-common-1.4-3  pipewire-0.2.7-1  startup-notification-0.12-3  xdg-desktop-portal-1.5.2-1  xdg-desktop-portal-kde-5.17.3-1  firefox-74.0.1-1

Total Download Size:    61.03 MiB
Total Installed Size:  267.27 MiB

:: Proceed with installation? [Y/n]
:: Retrieving packages...
 atk-2.26.0-1-x86_64                                                                    338.9 KiB  1473 KiB/s 00:00 [---------------------------------------------------------------------] 100%
 at-spi2-core-2.26.0-2-x86_64                                                           175.1 KiB  5.70 MiB/s 00:00 [---------------------------------------------------------------------] 100%
 at-spi2-atk-2.26.0-1-x86_64                                                             54.6 KiB  5.33 MiB/s 00:00 [---------------------------------------------------------------------] 100%
 mozilla-common-1.4-3-x86_64                                                           1240.0   B  0.00   B/s 00:00 [---------------------------------------------------------------------] 100%
 startup-notification-0.12-3-x86_64                                                      24.1 KiB  2.36 MiB/s 00:00 [---------------------------------------------------------------------] 100%
 xdg-desktop-portal-kde-5.17.3-1-x86_64                                                 117.5 KiB  11.5 MiB/s 00:00 [---------------------------------------------------------------------] 100%
 dav1d-0.3.1-1-x86_64                                                                   311.8 KiB  6.09 MiB/s 00:00 [---------------------------------------------------------------------] 100%
 pipewire-0.2.7-1-x86_64                                                                394.2 KiB  6.42 MiB/s 00:00 [---------------------------------------------------------------------] 100%
 geoclue-2.5.5-1-x86_64                                                                 160.2 KiB  5.22 MiB/s 00:00 [---------------------------------------------------------------------] 100%
 libportal-0.0.2-1-x86_64                                                                61.8 KiB  6.04 MiB/s 00:00 [---------------------------------------------------------------------] 100%
 xdg-desktop-portal-1.5.2-1-x86_64                                                      277.5 KiB  6.77 MiB/s 00:00 [---------------------------------------------------------------------] 100%
 gtk-update-icon-cache-3.24.5-1-x86_64                                                   15.0 KiB  1500 KiB/s 00:00 [---------------------------------------------------------------------] 100%
 gtk3-3.24.5-1-x86_64                                                                    10.5 MiB  5.39 MiB/s 00:02 [---------------------------------------------------------------------] 100%
 mime-types-9-1-x86_64                                                                   14.6 KiB  0.00   B/s 00:00 [---------------------------------------------------------------------] 100%
 firefox-74.0.1-1-x86_64                                                                 48.6 MiB  5.92 MiB/s 00:08 [---------------------------------------------------------------------] 100%
(15/15) checking keys in keyring                                                                                    [---------------------------------------------------------------------] 100%
downloading required keys...
:: Import PGP key BFD6ACBE02238B03, "Neofytos Kolokotronis <tetris4@chakraos.org>"? [Y/n]
error: key "BFD6ACBE02238B03" could not be looked up remotely
error: required key missing from keyring
error: failed to commit transaction (unexpected error)
Errors occurred, no packages were upgraded.
$ sudo pacman -S hplip
resolving dependencies...
looking for conflicting packages...

Packages (6) foomatic-db-engine-4.0_20161210-2  python-pyqt5-common-5.13.1-2  python3-dbus-1.2.4-1  python3-pyqt5-5.13.1-2  python3-sip-pyqt5-4.19.19-2  hplip-3.19.1-1

Total Download Size:   21.54 MiB
Total Installed Size:  58.48 MiB

:: Proceed with installation? [Y/n]
:: Retrieving packages...
 foomatic-db-engine-4.0_20161210-2-x86_64                                               149.8 KiB   789 KiB/s 00:00 [---------------------------------------------------------------------] 100%
 python3-sip-pyqt5-4.19.19-2-x86_64                                                      54.1 KiB  5.28 MiB/s 00:00 [---------------------------------------------------------------------] 100%
 python-pyqt5-common-5.13.1-2-x86_64                                                    508.9 KiB  4.14 MiB/s 00:00 [---------------------------------------------------------------------] 100%
 python3-pyqt5-5.13.1-2-x86_64                                                            3.3 MiB  6.09 MiB/s 00:01 [---------------------------------------------------------------------] 100%
 python3-dbus-1.2.4-1-x86_64                                                             92.1 KiB  4.50 MiB/s 00:00 [---------------------------------------------------------------------] 100%
 hplip-3.19.1-1-x86_64                                                                   17.4 MiB  5.80 MiB/s 00:03 [---------------------------------------------------------------------] 100%
(6/6) checking keys in keyring                                                                                      [---------------------------------------------------------------------] 100%
(6/6) checking package integrity                                                                                    [---------------------------------------------------------------------] 100%
error: python3-sip-pyqt5: signature from "Luca Giambonini <gluca86@gmail.com>" is unknown trust
:: File /var/cache/pacman/pkg/python3-sip-pyqt5-4.19.19-2-x86_64.pkg.tar.xz is corrupted (invalid or corrupted package (PGP signature)).
Do you want to delete it? [Y/n]
error: python-pyqt5-common: signature from "Luca Giambonini <gluca86@gmail.com>" is unknown trust
:: File /var/cache/pacman/pkg/python-pyqt5-common-5.13.1-2-x86_64.pkg.tar.xz is corrupted (invalid or corrupted package (PGP signature)).
Do you want to delete it? [Y/n]
error: python3-pyqt5: signature from "Luca Giambonini <gluca86@gmail.com>" is unknown trust
:: File /var/cache/pacman/pkg/python3-pyqt5-5.13.1-2-x86_64.pkg.tar.xz is corrupted (invalid or corrupted package (PGP signature)).
Do you want to delete it? [Y/n]
error: python3-dbus: signature from "Luca Giambonini <gluca86@gmail.com>" is unknown trust
:: File /var/cache/pacman/pkg/python3-dbus-1.2.4-1-x86_64.pkg.tar.xz is corrupted (invalid or corrupted package (PGP signature)).
Do you want to delete it? [Y/n]
error: hplip: signature from "Chaka Build Server (Automated Chakra Build System) <staff@chakralinux.org>" is unknown trust
:: File /var/cache/pacman/pkg/hplip-3.19.1-1-x86_64.pkg.tar.xz is corrupted (invalid or corrupted package (PGP signature)).
Do you want to delete it? [Y/n]
error: failed to commit transaction (invalid or corrupted package (PGP signature))
Errors occurred, no packages were upgraded.
Trying to solve

This being a well-known problem, I (re-)read more than just several posts on this very forum. I check chakra-keyring is installed, and attempt to re-initialise and repopulate it:

$ pacman -Q chakra-keyring
chakra-keyring 20190324-4

$ sudo pacman-key --init

$ sudo pacman-key --populate chakra
==> Appending keys from chakra.gpg...
==> Locally signing trusted keys in keyring...
  -> Locally signing key 0A1E9C2CA3EEDDCC211FC7C77E0B8AF94CA5A1FF...
  -> Locally signing key 2CC8A0609AD2A479C65B6D5C8E8B898CBF2412F9...
  -> Locally signing key 8CDCF01CD62948FC3E3FED0634592E24C51B9BC2...
  -> Locally signing key 5076CA6B47A352DECDDE23ABC4F76A333DB6614F...
  -> Locally signing key 52F0E68CB0E392747842EE7EE3DBE174DC2F4138...
  -> Locally signing key 23A1756DB842DD2F46945A3E9731B8FCED15437F...
  -> Locally signing key A9D40D9885046F71A2BDF5805A526467B6611E8A...
==> Importing owner trust values...
==> Updating trust database...
gpg: next trustdb check due at 2021-03-15

$ pacman -Qkk chakra-keyring
chakra-keyring: 8 total files, 0 altered files
Stuck!

Lastly, I attempt to refresh the keys from the server, and this is where I get stuck.

$ sudo pacman-key --refresh-keys
[sudo] password for reemz:
gpg: refreshing 9 keys from hkps://hkps.pool.sks-keyservers.net
gpg: keyserver refresh failed: General error
==> ERROR: A specified local key could not be updated from a keyserver.

Reinstalling chakra-keyring is a no-go as well:

$ sudo pacman -S chakra-keyring
[sudo] password for reemz:
warning: chakra-keyring-20190324-4 is up to date -- reinstalling
resolving dependencies...
looking for conflicting packages...

Packages (1) chakra-keyring-20190324-4

Total Download Size:   0.05 MiB
Total Installed Size:  0.06 MiB
Net Upgrade Size:      0.00 MiB

:: Proceed with installation? [Y/n]
:: Retrieving packages...
 chakra-keyring-20190324-4-any                                                           51.4 KiB   514 KiB/s 00:00 [---------------------------------------------------------------------] 100%
(1/1) checking keys in keyring                                                                                      [---------------------------------------------------------------------] 100%
(1/1) checking package integrity                                                                                    [---------------------------------------------------------------------] 100%
error: chakra-keyring: signature from "Chaka Build Server (Automated Chakra Build System) <staff@chakralinux.org>" is unknown trust
:: File /var/cache/pacman/pkg/chakra-keyring-20190324-4-any.pkg.tar.xz is corrupted (invalid or corrupted package (PGP signature)).
Do you want to delete it? [Y/n]
error: failed to commit transaction (invalid or corrupted package (PGP signature))
Errors occurred, no packages were upgraded.

So, save from the undesirable setting SigLevel to Never, what can I do to solve this?

Filed bug #392.