Solved, changed wordpress language settings and loco translation worked.
Problem solved with ZenCache plugin.
I solved problem with Gravity Forms and Gravity Approvals.
Website template is created with Artisteer, without heavy graphic. Even blank pages load slowly. Web server is virtual server with Ubuntu 14.04.
Network is with light traffic.
I tried, same result. I am not sure that I properly create iframe template. Can you provide more detailed procedure?
