valid ssl cert for a vip but getting connection not secure message

I have a VIP on f5 LTM ,where we are performing ssl offload have a valid third party signed cert for the vip. everything looks working fine . But what i observed is when I am trying to access the vip using IE or chrome i see that ( connection is not secure ). You have added a security exception for this site.

Why is that I am getting that error .

Please advise me.