Problem starting duplicati

Hello.

I haven’t backed up for a while and when I try to open duplicati I get this screen. I am using debian 12 and have upgraded duplicati to the latest version.

How can I access the interface?

Thank you.

How did you prefer to access it? Simplest is with a TrayIcon (maybe manual Duplicati start).
If you used systemd service, you might have just browsed to a URL, and not had tray icon.
If you used a URL, was it something like http://localhost:8200, or remote one, or what?
Some people also set up reverse proxy systems, where other new things might go wrong…

EDIT:

Is that an old tab? If so, try a refresh, or a hard refresh, or a new tab, then post what you do.
Just seeing end result doesn’t tell me any of that, and I’m not the developer, so won’t guess.

I access from the taskbar icon and that is the url that opens.
If I manually enter localhost:8200 it tells me the following:

If I click on login it asks me for a password.

I don’t know where that would be in your screenshot, but see TrayIcon for description.
This should sign you in automatically by filling in the field you show. You can also run

systemctl status duplicati to see if it looks like you are running the systemd one.
Trying to run both can make problems and confusion, so try to figure out what you run.

Since you have an existing install, Duplicati does not lead you through password setup.
I have been asking if it should. Regardless, you can add a password using directions at

Duplicati Access Password which will vary with your use. “If” on systemd, directions are
Example change with a different context

You can also work out what sort of Duplicati you use by finding its name in process view.
If you have an active TrayIcon on your task bar, it should have menu shown. Right click?

It looks like JWT Signin Token image tried an automatic signin, but didn’t work somehow.
Probably a developer would have to speak to that, but first find out what you are running.

Another way to guess at what you run is to look in ~root and your own ~ for the folder
.config/Duplicati to see which user you were running Duplicati as with the old install.

The URL is quite wrong and will not work. The url is not going through the server, but serving from a .cache folder. With this you cannot access the server, you need to use the localhost:8200 but I have no clue why the trayicon would ever open the file link?

As @ts678 mentions, you need to set a password. Depending on how you run Duplicati, there are different ways to do it: