Dekstop / mobile landing page is unavailable

Hello to All

website saddleonlineshop

I am getting an error on google ads and merchant center.

Error is

Desktop / mobile landing page is unavailable

I contact google and they advised

We’ve identified that your account was disapproved due to an Unavailable desktop /mobile landing page . Please be advised that I have carefully reviewed your account, after thorough investigation, we have determined that the website is directing to Page not found (404) then the website is working after 2 seconds. "

Google crawl the pages which resolved the issue but after two days I am again in same situation.

I was using below code in my theme liquid

{% if template == ‘404’ %}{% endif %}

I removed that code today , I do not know if this was an issue .

I need help to resolve this issue and help to redirect any or all 404 to homepage .

Any or all 404 means typo error url , changed url or moved / deleted item.

Please help

Thank you