Language Switcher issue

Hello.

– my permalinks settings-Post name
– i am using a static front page.
– my Polylang settings as below:
1. Default language – English
2. The language is set from the directory name in pretty permalinks
Example: http://cookkoo/en/my-post/
3. Remove /language/ in pretty permalinks
Example: http://cookkoo/en/
4. Detect browser language – When the front page is visited, set the language according to the browser preference
5. Media – Activate languages and translations for media
6. Synchronization – Check all options.

I uses Loco translate to translate 13 language. my issue as below:
-If i disable Polylang, Home page and others page is display and work fine.
-If i enable Polylang, Home page is work fine,but DOUBLE display Language Switcher at TopMenu, and i test it by add Language Switcher to NavMenu too, and it display correct (No Double Language Switcher), but others page display white page.

Please help.
Thank you

https://wordpress.org/plugins/polylang/