urgent help WideIP not coming up post upgrade

Hi,

I just upgraded a GTM running 10.2.4 to 11.5.3. However post upgrade WideIP's are being marked down. Upon investigating further found that pool members are in Red Diamond and its displaying "no response from Big3d". I checked the big3d service and its running. Also I have removed the GTM from Sync group

However now although its saying as "success" the pool members are still in Red. Can anyone help with whats happening I am currently in a maintainence window need urgent help