3500 Cummins battery replacement problem

[HtwnRam]

I have replaced batteries on my 2019 3500 DRW. Both positive leads are on positive post.
When I try to connect the ground to negative post, my horn starts honking.

Any ideas?

 

[H3LZSN1P3R]

Thats a new one try putting the leads on then hitting the panic button on the FOB to turn the honking off?