Error 404 after changing http to https

Hi there.
I wanted to install ssl certificates and i did everything according to instructions.
1. I changed 2 urls in options of wordpress.
2. I rewrote htaccess file
3. I ran Let’s Ecrypt certificate.
After this I see error 404 and i cannot login to wordpress admin panel.
In Instalatron on host admin menu i see red warning “error, page not found”.
I tried to deactivate ssl and restore htaccess file. Also i tried to restore original http adress of my main page by php admin. Although i have restored everything to the original, I still have 404 error and red warning “error, page not found” in Instalatron.
Where can i search the problem?
I am new in wordpress and cannot solve this problem…

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