Menu changed to pages’ names after installation

Hi,

After installing the Polylang plugin on my website and configuring the primary and secondary languages(basic setup after installation), I noticed that my menu now displays the names of the pages instead of the custom menu I originally set up. Upon checking my menu settings, I confirmed that they remain unchanged. I’m unsure what caused this alteration on my website. Any help will be appreciated! Thanks ahead!!

Note: I deactivate the plugin due to the menu does not show as I expected currently.

The page I need help with: [log in to see the link]