Server crashes exactly at sql async reader

I resolved it by forcing async but with ConfigureAwait(false) as:

public async Task<Timezone> GetTimezoneAsync(int componentId, string componentType)
{
    string connectionStringElements = ""; //connection string

    await using var sqlConnection = new SqlConnection(connectionStringElements);
    await sqlConnection.OpenAsync().ConfigureAwait(false);

    await using var command = new SqlCommand("GetTimezone", sqlConnection)
    {
        CommandType = CommandType.StoredProcedure,
        CommandTimeout = 120
    };

    command.Parameters.Add("@ComponentId", SqlDbType.Int).Value = componentId;
    command.Parameters.Add("@ComponentType", SqlDbType.VarChar).Value = componentType;

    await using var reader = await command.ExecuteReaderAsync().ConfigureAwait(false);

    Timezone timezone = new Timezone();
    if (await reader.ReadAsync().ConfigureAwait(false))
    {
        timezone = new Timezone
        {
            TimezoneId = reader["TimeZoneKey"] != DBNull.Value ? Convert.ToInt32(reader["TimeZoneKey"]) : 0,
            WindowsName = reader["TimeZoneWindowsName"] != DBNull.Value ? Convert.ToString(reader["TimeZoneWindowsName"]) : null
        };
    }

    return timezone;
}

Adding .ConfigureAwait(false) was the key ✅. That tells the async call not to try resuming on Blazor Server’s synchronization context (which was causing the crash / circuit disconnect before).

🔑 Why this version works

• await using ensures SqlConnection, SqlCommand, and SqlDataReader are all disposed properly, even if exceptions occur.

• ConfigureAwait(false) prevents Blazor Server’s SignalR synchronization context from deadlocking when waiting on async SQL calls.

• Still fully asynchronous — so your server can scale better under concurrent users than with sync DB calls.