qTranslate-X return to original language

good evening,
I installed the qTranslate X plugin on-site “https://www.the-differences.it/home/”.
There is one switch languages in the menu.
The main language is Italian and on by the switch you can select English.
I have the problem that when I select the English language if I wanted to return to the Italian language I can not, remains on the English version.

How should I do?

the code I entered for the switch is as follows:

<Div class = “lang-sel sel-dropdown”>

<Span> Lang </ span>

• Lang
  </ Li>
• It
  </ Li>
• En
  </ Li>
  </ Ul>
  </ Div>

  can you help me?