Hi Lulia,
Greetings from Syncfusion support!
We have checked with your reported issue “Connection is lost” and this is not an issue also the default behavior of Blazor. Blazor won’t refresh the browser automatically. If the server is restarted then there is no way for the app to reconnect back to the same state because the server state is gone. The only way forward is to refresh the browser.
Kindly get back to us, If you need further assistance
Regards
Alagumeena.K