@VistaLover, @Mathwiz, @NotHereToPlayGames, @anton12!
Thank you all for your investigations, advices, and tips! Yesterday I only had a little time. I just wanted to book cinema tickets quickly, and that was more of an odyssey on my old computer. Maybe, it was my own stupidity, I could have used my Android tablet directly. BTW, the movie "Top Gun - Maverick" was simply great! At home again, I opened the problematic website www.uci-kinowelt.de in Serpent 52 (2022-09-10), and it worked perfectly with a very fast and successful security check for my slow computer without any annoying captcha. That surprised me. Next, I opened it with a new profile in New Moon 28 (2022-09-10), and suddenly, what can I say, it worked there, too. Thanks @VistaLover and @anton12 for your confirmation! In both cases, palefill 1.20 was installed. I still have to investigate why the security check cannot be completed successfully in my main profile of NM 28. Unfortunately, the 360Chrome browsers were no help in this case. I can say one thing with all clarity: I abysmally hate these sites with a so-called security check.
Cheers, AstroSkipper