Preload interrupted and stopped – Support solved it

I tried to solve it on my own for weeks. Had a green google-Ranking, but 6 weeks ago it crashed to all red. Tried a lot. And nevertheless the caching didnt work as supposed to do. Tried 1000 varieties of settings and tests. Nothing worked sustainable.
Support then gave me the advice to set the factor of preloaded sites to 4 (and not 8 or higher as I did). I use IONOS normal webspace, no cdn.
Now the Preload works. I dont understand the logic behind, maybe the shared server was overload and 10 or even 12 attempts to cache per minute was too much.
Thanks! Marc