Hi there Kai_05i,
Welcome to Apple Support Communities. We suggest resetting the network settings to resolve this trouble you're having. The steps can be found in the related Apple Support article: If your iPhone, iPad, or iPod touch won't connect to a Wi-Fi network - Apple Support
"Still can't connect?
Reset your Network Settings. If you're using iOS or iPadOS 15 or later, tap Settings > General > Transfer or Reset [Device] > Reset > Reset Network Settings. If you're using iOS or iPadOS 14 or earlier, tap Settings > General > Reset > Reset Network Settings. This also resets Wi-Fi networks and passwords, cellular settings, and VPN and APN settings that you've used before."
Should this issue persist, get in touch with Apple Support for further assistance:
Get Support
We hope this helps you.
Cheers!