Hi there, Hgabriele!
Thanks for reaching out to the Apple Support Communities! It sounds like you are having an issue with Safari being unable to open a webpage on your iPad and I’m happy to help! You’ve tried excellent steps resetting the network settings and clearing the website history and data and I suggest checking out this article for steps to take If Safari displays a blank page or quits on your iPhone, iPad, or iPod touch. This article will give you additional steps you can try for troubleshooting your issue.
Have you noticed the issue happening on only one specific website for an all websites you attempt to access? Does the issue happen on Wi-Fi only, cellular data, or both?
Let me know the results and take care!