We have a multiple environments and I have upgraded the Third party application on windows 2008R2 and host website on it. Everything is working fine but the problem is users facing time out error after 10-15mints, I've increase the time out session limit to 1800 sec in IIS but still facing the same issue. There is no issue with prod just only UAT and PERF environment. Prod not upgraded yet. Is this is the network issue or website....????????