I wanted to run SSL on my website (tomcar24.pl) but I can't probably due to console error:

I tried to find that old domain geriamedica.pl (I used it while developing website) but can't at all. I have downloaded all possible folders - theme and plugins - didn't find anything. Changed theme to default and errors was gone so problem is probably somewhere in theme. Also checked file generating error in wp-includes but there's no such domain. What else could I do? That error appears only on homepage - subpages and wpadmin are totally fine and working.

What should I do and check now?