When I try to upgrade to from 18.04 to 20.04 I get a message saying that my Authentication has failed and the problem might be either with my internet connection (since I can connect to email, youtube, etc. the internet connection is OK) or a problem with the server. I assume that means the Ubuntu server. How can I troubleshoot a problem connecting to that server?

would be nice to give us some details about what did you try exactly (which commands, what was the response....)

More information: From Software Updates, I ensure 18.04 has all current updates applied. I then get a message that the new version, 20.04 is available with a button to "Upgrade." I hit "Upgrade" and I get a request to "Authenticate" my request with my password, which I enter, and I get a message box with links to "What's new in 20.04", Ubuntu questions, etc. and this message box has a button at the bottom to "Upgrade", which I hit and then I get the message that my authentication has failed with the two suggestions; either I don't have an Internet connection or the server is unavailable. I have a "test installation" of Ubuntu on my sda7 partition and I went through exactly the same steps that I just outlined. I did not run into any issues at all and successfully upgraded that version 18.04 to 20.04.

One thing just crossed my mind.

Is your 18.04 32 bits?
If so, you cannot upgrade directly.

If you are running x64, have you attempted to upgrade by running this command from the command line?

sudo sudo update-manager -c

Show the output of

Well, it's now the middle of Feb. and I'm no closer to upgrading my main system from 18.04 to 20.04 than I was about 3 months ago. From time to time I get a notification that version 20.04 is available, asking if I would like to upgrade. I try to upgrade and the upgrade stops in the same place as always. It appears the server, as in the server from which new versions are downloaded, is trying to install either version 14.04 or 16.04 and, therefore, fails. Does anyone have any thoughts about why this might be happening or how I can troubleshoot the problem.

1) Could there still be enabled some 14.04 or 16.04 repositories in your /etc/apt/sources.list? Actually, /etc/apt/sources.list and /etc/apt/sources.list.d/*.list are the first things I would check if a system upgrade failed. I usually disable any third-party repositories before attempting a system upgrade.

2) Try upgrading from the command line via do-release-upgrade. Even if not successful, it may give you some additional hints as to what went wrong.

Thank you for your response.
I tried installing from the command prompt and this is what I got;
root@vesalius:~# do-release-upgrade
Checking for a new Ubuntu release
Get:1 Upgrade tool signature [1,554 B]
Get:2 Upgrade tool [1,341 kB]
Fetched 1,343 kB in 0s (0 B/s)
authenticate 'focal.tar.gz' against 'focal.tar.gz.gpg'
Authentication failed
Authenticating the upgrade failed. There may be a problem with the network or with the server.

Issuing the cat /etc/apt/sources.list command here's part of what I got;
Checking for a new Ubuntu release
Get:1 Upgrade tool signature [1,554 B]
Get:2 Upgrade tool [1,341 kB]
Fetched 1,343 kB in 0s (0 B/s)
authenticate 'focal.tar.gz' against 'focal.tar.gz.gpg'
Authentication failed
Authenticating the upgrade failed. There may be a problem with the network or with the server.
root@vesalius:~#
root@vesalius:~# cat /etc/apt/sources.list
# deb cdrom:[Ubuntu 16.04 LTS _Xenial Xerus_ - Release amd64 (20160420.1)]/ xenial main restricted
# deb cdrom:[Ubuntu 12.04 LTS _Precise Pangolin_ - Release i386 (20120423)]/ precise main restricted
...
## Uncomment the following two lines to add software from Canonical's
## 'partner' repository.
## This software is not part of Ubuntu, but is offered by Canonical and the
## respective vendors as a service to Ubuntu users.
deb http://archive.canonical.com/ubuntu bionic partner
deb-src http://archive.canonical.com/ubuntu bionic partner

I've searched for those two lines and cannot find them. Where would they reside?

Your /etc/apt/sources.list is incomplete. There should be more repositories enabled beyond partner. See this question on Ask Ubuntu.

Add these lines at the end of the file:

Run all the commands and post the full output to the forum.

First, thank you both for responding. I truly appreciate this. I'm not new to computers (hardware or software) and I'm not new to having Linux/Ubuntu on my PC BUT you need to treat me like an absolute beginner in regards to the innards of the OS. My knowledge and experience of operating systems is from 25 years ago on VMS (if anyone even knows that acronym any more).

shruggy; I don't understand what file I would add the the lines "deb http://archive..." etc.etc. to. Also, I looked at 'this question' on Ask Ubuntu and it appears others have had the a similar problem that I am but I was a bit lost regarding what they were doing to solve the problem.

Pentium4User; Listed below are the outputs from each of the commands.

craig@vesalius:~$ lsb_release -a
LSB Version: core-9.20170808ubuntu1-noarch:cxx-3.0-amd64:cxx-3.0-noarch:cxx-3.1-amd64:cxx-3.1-noarch:cxx-3.2-amd64:cxx-3.2-noarch:cxx-4.0-amd64:cxx-4.0-noarch:cxx-4.1-amd64:cxx-4.1-noarch:desktop-3.1-amd64:desktop-3.1-noarch:desktop-3.2-amd64:desktop-3.2-noarch:desktop-4.0-amd64:desktop-4.0-noarch:desktop-4.1-amd64:desktop-4.1-noarch:graphics-2.0-amd64:graphics-2.0-noarch:graphics-3.0-amd64:graphics-3.0-noarch:graphics-3.1-amd64:graphics-3.1-noarch:graphics-3.2-amd64:graphics-3.2-noarch:graphics-4.0-amd64:graphics-4.0-noarch:graphics-4.1-amd64:graphics-4.1-noarch:languages-3.2-amd64:languages-3.2-noarch:languages-4.0-amd64:languages-4.0-noarch:languages-4.1-amd64:languages-4.1-noarch:multimedia-3.2-amd64:multimedia-3.2-noarch:multimedia-4.0-amd64:multimedia-4.0-noarch:multimedia-4.1-amd64:multimedia-4.1-noarchrinting-9.20170808ubuntu1-noarch:qt4-3.1-amd64:qt4-3.1-noarch:security-9.20170808ubuntu1-noarch
Distributor ID: Ubuntu
Description: Ubuntu 18.04.1 LTS
Release: 18.04
Codename: bionic

craig@vesalius:~$ lscpu
Architecture: x86_64
CPU op-mode(s): 32-bit, 64-bit
Byte Order: Little Endian
CPU(s): 4
On-line CPU(s) list: 0-3
Thread(s) per core: 1
Core(s) per socket: 4
Socket(s): 1
NUMA node(s): 1
Vendor ID: GenuineIntel
CPU family: 6
Model: 42
Model name: Intel(R) Core(TM) i5-2400 CPU @ 3.10GHz
Stepping: 7
CPU MHz: 3046.074
CPU max MHz: 6300.0000
CPU min MHz: 1600.0000
BogoMIPS: 6387.29
Virtualization: VT-x
L1d cache: 32K
L1i cache: 32K
L2 cache: 256K
L3 cache: 6144K
NUMA node0 CPU(s): 0-3
Flags: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc cpuid aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic popcnt tsc_deadline_timer aes xsave avx lahf_lm epb pti ssbd ibrs ibpb stibp tpr_shadow vnmi flexpriority ept vpid xsaveopt dtherm ida arat pln pts md_clear flush_l1d

craig@vesalius:~$ lscpu
Architecture: x86_64
CPU op-mode(s): 32-bit, 64-bit
Byte Order: Little Endian
CPU(s): 4
On-line CPU(s) list: 0-3
Thread(s) per core: 1
Core(s) per socket: 4
Socket(s): 1
NUMA node(s): 1
Vendor ID: GenuineIntel
CPU family: 6
Model: 42
Model name: Intel(R) Core(TM) i5-2400 CPU @ 3.10GHz
Stepping: 7
CPU MHz: 3046.074
CPU max MHz: 6300.0000
CPU min MHz: 1600.0000
BogoMIPS: 6387.29
Virtualization: VT-x
L1d cache: 32K
L1i cache: 32K
L2 cache: 256K
L3 cache: 6144K
NUMA node0 CPU(s): 0-3
Flags: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc cpuid aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic popcnt tsc_deadline_timer aes xsave avx lahf_lm epb pti ssbd ibrs ibpb stibp tpr_shadow vnmi flexpriority ept vpid xsaveopt dtherm ida arat pln pts md_clear flush_l1d
craig@vesalius:~$ cat /etc/apt/sources.list
# deb cdrom:[Ubuntu 16.04 LTS _Xenial Xerus_ - Release amd64 (20160420.1)]/ xenial main restricted
# deb cdrom:[Ubuntu 12.04 LTS _Precise Pangolin_ - Release i386 (20120423)]/ precise main restricted

# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb http://us.archive.ubuntu.com/ubuntu/ bionic main restricted
deb-src http://us.archive.ubuntu.com/ubuntu/ bionic main restricted

## Major bug fix updates produced after the final release of the
## distribution.

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team. Also, please note that software in universe WILL NOT receive any
## review or updates from the Ubuntu security team.
deb http://us.archive.ubuntu.com/ubuntu/ bionic universe
deb-src http://us.archive.ubuntu.com/ubuntu/ bionic universe

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team, and may not be under a free licence. Please satisfy yourself as to
## your rights to use the software. Also, please note that software in
## multiverse WILL NOT receive any review or updates from the Ubuntu
## security team.
deb http://us.archive.ubuntu.com/ubuntu/ bionic multiverse
deb-src http://us.archive.ubuntu.com/ubuntu/ bionic multiverse

## N.B. software from this repository may not have been tested as
## extensively as that contained in the main release, although it includes
## newer versions of some applications which may provide useful features.
## Also, please note that software in backports WILL NOT receive any review
## or updates from the Ubuntu security team.
deb http://us.archive.ubuntu.com/ubuntu/ bionic-backports main restricted universe multiverse
deb-src http://us.archive.ubuntu.com/ubuntu/ bionic-backports main restricted universe multiverse

deb http://security.ubuntu.com/ubuntu bionic-security main restricted
deb-src http://security.ubuntu.com/ubuntu bionic-security main restricted
deb http://security.ubuntu.com/ubuntu bionic-security universe
deb-src http://security.ubuntu.com/ubuntu bionic-security universe
deb http://security.ubuntu.com/ubuntu bionic-security multiverse
deb-src http://security.ubuntu.com/ubuntu bionic-security multiverse

## Uncomment the following two lines to add software from Canonical's
## 'partner' repository.
## This software is not part of Ubuntu, but is offered by Canonical and the
## respective vendors as a service to Ubuntu users.
deb http://archive.canonical.com/ubuntu bionic partner
deb-src http://archive.canonical.com/ubuntu bionic partner

# deb http://www.openprinting.org/download...driver/debian/ lsb3.2 contrib # disabled on upgrade to bionic
# deb http://archive.ubuntu.com/ubuntu/ trusty main

craig@vesalius:~$ cat /etc/apt/sources.list.d/*
cat: '/etc/apt/sources.list.d/*': No such file or directory

Scrap this. The output in your post #11 above differs from what it was in #8. Looks like you omitted some parts of the output in #8. This makes my previous response irrelevant.

Instead, try

probably the following helps:

shruggy; My apologies, I used ellipses to indicate that I had left some things out. I included only those lines that I thought were relevant.

pan64; I issued each command you listed and all seemed to work just fine with a couple of them indicating there were 4 packages that were automatically installed, were no longer needed and could be removed. Is it possible one of these 4 packages could be causing the problem? The actual do-release-upgrade command gave me the same error I've been getting anytime I try to upgrade. See below;
do-release-upgrade
Checking for a new Ubuntu release
Get:1 Upgrade tool signature [1,554 B]
Get:2 Upgrade tool [1,341 kB]
Fetched 1,343 kB in 0s (0 B/s)
authenticate 'focal.tar.gz' against 'focal.tar.gz.gpg'
Authentication failed
Authenticating the upgrade failed. There may be a problem with the network or with the server.

Have you reinstalled ubuntu-keyring?

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