Issue with new VeriSign certificate clients unable to access website we went from sha 128 to sha-256

What hardware are you running on? Not seen any issues with sha-256, but we had and issue with a client ssl profile change(removing insecure protocols)under 11.4 Exactly the same issue i.e web page wouldn't always render correctly when backed out everything worked . It only seemed to affect our 2000s and 4000s hardware, In the end we fixed by upgrading to 11.6 HF1. The only thing we could put it down to was a possible issue flagged under SOL15232. Just a thought.