Ios Build freezes when i click a button to switch Scenes

Hi :D,
I have a problem, my app freezes when i click a button to switch Scenes :c. The first Scene has only one button and this button does work, but the second Scene has 17 Buttons and when i click one the game freezes and after 2 or 3 Minutes the Scene is loaded. But when i turn off my internet the Scene is loaded directly. Sry for my bad english, i am actually a german :D.

First Scene Code:
public void Click () {
BackFor.bew(“Main”);
SceneManager.UnloadSceneAsync(“Start”);
SceneManager.LoadScene(“Main”, LoadSceneMode.Single);
}

Second Scene Code:

public void load()
{
BackFor.bew(“Anzeigedauer”);
SceneManager.UnloadSceneAsync(“Main”);
SceneManager.LoadScene(“Anzeigedauer”, LoadSceneMode.Single);
}

I am sry, it wasnt the change of the scene it was a other script, which tried to connect to a server which isnt started, so it freezed.