Apt repository error: The TLS connection was non-properly terminated

I have a problem in installing “Setup LoRa Server software repository
”. When I run “sudo apt update”
prompt,I got this error

Err:6 Index of /packages/1.x/deb/ stable Release
gnutls_handshake() failed: The TLS connection was non-properly terminated.
Reading package lists… Done
E: The repository ‘https Index of /packages/1.x/deb/ stable Release’ does not have a Release file.
N: Updating from such a repository can’t be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.

I use Ubuntu 16.04.4.
Please help me.

Could you confirm you have the following line in your apt configuration?

deb https://artifacts.loraserver.io/packages/1.x/deb stable main

Yes ,I have this line in path :"/etc/apt/sources.list.d/loraserver.list".

Are you sure this is not a proxy / firewall issue. I can’t reproduce your issue:

root@iot-test:~# cat /etc/apt/sources.list.d/loraserver.list
deb https://artifacts.loraserver.io/packages/1.x/deb stable main

root@iot-test:~# apt update
Hit:4 http://ppa.launchpad.net/certbot/certbot/ubuntu xenial InRelease
Hit:1 http://lon1.mirrors.digitalocean.com/ubuntu xenial InRelease
Get:2 http://lon1.mirrors.digitalocean.com/ubuntu xenial-updates InRelease [109 kB]
Get:3 http://lon1.mirrors.digitalocean.com/ubuntu xenial-backports InRelease [107 kB]
Get:5 http://security.ubuntu.com/ubuntu xenial-security InRelease [107 kB]
Get:6 http://apt.postgresql.org/pub/repos/apt xenial-pgdg InRelease [46.5 kB]
Hit:7 https://artifacts.loraserver.io/packages/1.x/deb stable InRelease
Get:8 http://lon1.mirrors.digitalocean.com/ubuntu xenial-updates/main amd64 Packages [783 kB]
Get:9 http://lon1.mirrors.digitalocean.com/ubuntu xenial-updates/universe amd64 Packages [631 kB]
Fetched 1,783 kB in 1s (1,566 kB/s)
Reading package lists... Done
Building dependency tree
Reading state information... Done
3 packages can be upgraded. Run 'apt list --upgradable' to see them.
root@iot-test:~#

root@ubuntu:/# echo $http_proxy

root@ubuntu:/# sudo ufw status
Status: inactive
root@ubuntu:/# apt update
Get:1 Index of /ubuntu xenial InRelease [247 kB]
Hit:2 Index of /ubuntu xenial InRelease
Ign:3 Index of /packages/1.x/deb/ stable InRelease
Get:4 Index of /ubuntu xenial-updates InRelease [109 kB]
Get:5 Index of /ubuntu xenial-backports InRelease [107 kB]
Get:6 Index of /ubuntu xenial-security InRelease [107 kB]
Err:7 Index of /packages/1.x/deb/ stable Release
gnutls_handshake() failed: Error in the pull function.
Reading package lists… Done
E: The repository ‘Index of /packages/1.x/deb/ stable Release’ does not have a Release file.
N: Updating from such a repository can’t be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.

I think that proxy / firewall is off.

finally I installed component by downloading package and then installing.