website slow on connecting with server waterfall

my website is slow with connecting server in waterfall for 1.30-1.5s.
That is fast when load other files.
I check pingdom and gtmetrix all get same result.
I try to upgrade server and change plug,W3 total.Does not work at all.
https://tools.pingdom.com/#!/brCDFr/maluntan.com

I am wondering how could I improve this.
Thank you all!
Tony