Most verification is undecidable, lots of it is pspace complete. That doesn’t mean very much in practice since those are worst case bounds. People regularly solve problems that are undecidable for all practical instances that they care about.
Verifying behaviour of an arbitrary program is uncomputable. However that doesnt mean you can't have proofs of behaviour of specific programs you create.
Personally i have some doubts, a lot of research has gone into the idea without much to show for it, but its a very reasonable research area.