It is heavy loaded, some requests work some don't. A site on a single server like here is not made for thousands of bot requests per second
Maybe I should at some point consider using Cloudflare services.

Enabling the bot filter may help a little, but since some of these new bots are not filtered by it, it won't solve all issues.

I've enabled the bot block a couple times already today

500 Internal Server Error on the main site . Happened twice today ( don't remember the time for the 1st one , 8:54 PM ( Baube's time ) for the second one

I added a bunch of the fake browser IDs to the list of bots, hoping among these there isn't one of a real browser (well, some are, but old outdated versions, most likely).
But even with that, these are so aggressive that I don't know if the site can work without the bot filter when they are scraping it. Maybe for some like that I should add a permanent filter then, I'll try to do that in the next days. Hoping that they don't start using real current browser IDs (instead of some that are just similar).

If someone gets blocked because identified as a bot, please open https://ksle1.antp.be/user-agent.php and give the ID that is returned for your browser.

I made some minor changes to slow a little the site for non logged in users, and disabled the stats page for these too (as it is quite heavy), that will already help a little for unidentified bots (until one creates an account...)
I'll try to also make a better filter for bots in the next days, but I can't do miracles