Sambucus are prone to stem and branch cankers. Check for sunken areas on the stems or branches and prune out if located. If the cankers reach the main trunk, you have likely lost your shrub :-( Elderberry shoot borers are also a possibility, so check for holes low on the stems.

Are you sure this is 'Sutherland Gold'? I grew this elder in my old garden and the leaves were bright golden yellow, not at all green as yours appears to be.

Oh dear. At first I didn't see anything, but then I spotted this on the base trunk:

so the tree is doomed. It's sad, but on the plus side, I have a a species seedling I've been looking for a place to plant.

This fellow was bought as a sutherland gold and had yellow new growth, but it's in shade so leaves darkened to a green.

thank you for your help. Bad news, but better to know now so I can get it out of there.