Update Failure

Hello Sophos Community,

I am a new user of the Linux standalone version. When I try to update with the following command:

sudo /opt/sophos-av/bin/savupdate

I receive the following error message:

Failed to download 'sdds:SOPHOS': invalid authentication. Please check PrimaryUpdateUsername and PrimaryUpdatePassword.
Failed to replicate from all update sources

My PrimaryUpdateUsername is my email address.

Some of the responses on the community bulletin board suggest uninstalling and reinstalling. I have tried this twice, first setting the username to another username, then setting it back to my email address.

/opt/sophos-av/bin/savdstatus --version 

... gives the following information. Note that the latest threat data release is about 6 months old.

Copyright 1989-2021 Sophos Limited. All rights reserved.
Sophos Anti-Virus = 9.17.1
Build Revision = 2858276
Threat detection engine = 3.83.1
Threat data = 5.85
Threat count = 63652814
Threat data release = Tue 22 Jun 2021 12:00:00 AM  

user.txt confirms that my user name is my email address:

PrimaryUpdateUsername: <my email>

where <my email> is my actual email address.

Here is my full installation setup:

==============================

I accept the Sophos End User License Agreement and acknowledge the Sophos Privacy Policy. Yes(Y)/No(N) [N]
> Y

Where do you want to install Sophos Anti-Virus? [/opt/sophos-av]
>

Do you want to enable on-access scanning? Yes(Y)/No(N) [Y]
> Y

Sophos recommends that you configure Sophos Anti-Virus to auto-update.

It can update either from Sophos directly (requiring username/password details) or from your own server (directory or website (possibly requiring username/password)).

Which type of auto-updating do you want? From Sophos(s)/From own server(o)/None(n) [s]
> s

Updating directly from Sophos.
Username for Sophos updates? []
> Password for Sophos updates?
> <my email>

Do you need a proxy to access Sophos updates? Yes(Y)/No(N) [N]
> N

Installing Sophos Anti-Virus....
Selecting appropriate kernel support...
When Sophos Anti-Virus starts, it updates itself to try to find a Sophos kernel interface module update. This might cause a significant delay.
Sophos Anti-Virus starts after installation.

Installation completed.
Your computer is now protected by Sophos Anti-Virus.

==============================

Some advice suggests that that I use the sophos ID. This is my email address. However, the advice says that it cannot be the email address. This appears to be incorrect advice because I tested setting it to another sophos ID upon installation. One message suggested that a new user is assigned an ID by Sophos, but this is not the case at least on this version of Sophos.

Another thread suggested that a user had selected proxy, without specifying proxy details. That person reinstalled without selecting proxy. This solution does not work for me since I have not selected proxy.

Does anyone have a solution?

Thanks,

Joe