[Duplicity-talk] Serious problem with duplicity - secret key not available

[Luca Bertoncello]

Hi list!

I'm using Duplicity on many servers since years and did not even have a 
problem...

Now I have to backup a server (very old... it runs Ubuntu 16.04 and I cannot 
upgrade it now).
So I installed duplicity 0.7.06 from Ubuntu-Repository (GPG is 1.4.20) and 
started the backup.

It works, but after some days it does not work anymore I every call to 
duplicity fails with:

GPGError: GPG Failed, see log below:
===== Begin GnuPG log =====
gpg: encrypted with 2048-bit RSA key, ID xxxxxxx, created 2021-07-19
"RESTORE <it@queo-group.com>"
gpg: decryption failed: secret key not available
===== End GnuPG log =====

The key files are on the disk and readable.

Do someone have an idea what I can do?

I already had the problem on the server and I "solved" it creating new keys and 
deleting all old backups, but this is not a solution...

Thanks a lot
Luca