I changed the * as an IP setting in the website settings page, then I restarted apache.
then I deactivated the website throught the same interface and reactivated it.
then I restarted apache again.
the bahavior changes. the "bad request" error page is now styled in ISPC style. it still says "bad request" but with "error 400"
ERROR 400 - Bad Request!
The following error occurred:
You have used invalid syntax.
Please contact the webmaster with any queries.
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So there seems to be a small bug that settings are not properly written to DB unless the site is deactivated and reactivated.
But my problem remains, the site still doesn't appear.