Witam Panie Adrianie,
I scanned one of the links you gave for recommendations (hints towards improvement e.g. security improvement),
and it came up with some 200 issues:
https://webhint.io/scanner/3d28d568-67c6-4138-9d97-805c21231595See particularly:
https://webhint.io/scanner/3d28d568-67c6-4138-9d97-805c21231595#category-securityCertainly that http site has some backlying php problems at the webserver and as you saw it is not only avast to complain about that.
But it is not that the blocking is about.
See:
<!DOCTYPE html><html lang="en" data-adblockkey=MFwwDQYJKoZIhvcNAQEBBQADSwAwSAJBANnylXXXXXXXXXXXXXXXXXXXXvjFUCsdFlb6TdQhxb9RXWXuI4t31c+o8fYOv/s8q1LGPga3DE1L/tHU4LENMCAwEAAQ==_vgqARs6XTetJ9eDkEAigNmOH0gI5oDHVDcJDA1yqXazCcWPMB7YBiWBbQDicgeQD0aSb9mBSmBlUDES6V4hqeQ==><head><meta charset="utf-8"><title>lak.pl - This website is for sale! - Lak Resources and Information.</title><meta name="viewport" content="width=device-width,initial-scale=1.0,maximum-scale=1.0,user-scalable=0"><meta name="description" content="This website is for sale! -lak.pl is your first and best source for all of the information you’re looking for. From general topics to more of what you would expect to find here, -lak.pl has it all. We hope you find what you are searching for!"><link
XXXXXX obfuscated by me for obvious reasons (pol).
"Your site" has been sedo-parked and is earning adclicks for ABP "from the grave" (as it is for sale).
Now a rogue can't just copy someone else's "data-adblockkey" for their own site: -http://img.sedoparking.com","adblockkey":" data-
Spammy looking links: Any links with funky anchor text? Yes there are.
<a href="-http://lakp.pl/wyniki.php?roundId=642">Moore - Git Team 4-3 (3-0)<br> Adampol - Poker 6-1 (2-1)<br> Nexbet - Krupniki 4-3 (0-2)<br> Dywany - APP Energy 5-7 (2-2)<br> Bosko - Tifosi 5-3 (2-1)<br> Czarni - Politechnika 4-2 (1-1)</a>
<a style="text-decoration: none !important; color: #302c7f;" href="-klub.php?teamId=46">Poker</a> To wszystko (pol).
pozdrawiam,
polonus (volunteer 3rd party cold recon website security analyst and website error-hunter)