Page not getting redirected properly I'm only using i18n and not Entity Translation.

I've an English version of page set as front page( node/page1).

I've restarted working on my multilingual site after 2 months and previously it was working fine. 
Earlier I had added French, German, etc translated version of this page.

So if I go to mysite.com/de or mysite.com/fr those translated pages are shown automatically(in short existing translated pages are getting redirected correctly). 

But now (after 2 months) when I add translation for untranslated languages like "it" then mysite.com/it does not redirect to the Italian version of the home page.

I've Global Redirect, Translation Redirect enabled. I've also tried clearing all cache several times.

What could be the problem?
Your problem might be because of the "language detection" configuration. 

So check this configuration via Configuration -> Languages -> detection and selection: the order should be 'URL, Default, User', and not something like 'Default, URL, User'.