Aerowinder said

Adding manual exclusions is not something I want to do.

Hello Aerowinder,

This may not be what you want, but would you do this please :

Options => Privacy & Security

Under Forms and Passwords :

Next to 'Ask to save logins and passwords for sites' you'll see : 'Exceptions' - click on that and enter the site(s) you don't want to save logins and passwords for.

Would that work for you  ?

Greetings,

This will work, but I don't want to do this manually for all of my server logins. I thought maybe I couldn't see the feature because I'm logged into my Sync account? I know it used to be there in the past. When did they remove it?

When exactly the option "Never Save" was removed, I don't
know - it's not because you use Sync, though.

As you say in your original post "I am unable to permanently
decline saving a password for a single site ", I didn't think
it would be all that much work, as it sounded as if it's for one site only .....

Unchecking the box "Ask to save logins and passwords for sites" wouldn't be an option either, so entering the sites in the "Exceptions" box (just once) is the only thing I can think of (keeping my fingers crossed that you won't have to do it for a lot of sites .... )

The "Don't Save" button has a down pointing arrow next to it. If you click this arrow then you get the "Never Save" choice to create a block exception.

As cor-el provided the correct answer, would you be so kind as
to remove the Chosen Solution mark from my post  ?

You can do so by clicking on the "Undo" button and then mark
cor-el's post as Chosen Solution.

Thank you in advance  !