問合せの文面作ってみました。もしよかったらどうぞ。To whom it may concern,My system shows error code 300 from June 7th.The details are as follows.(エラーメッセージ一式を書く).Just before this trouble, I was seeing a loading mark above display throughout my match.I always play DbD on steam.Could you tell me how to solve this problem?Thanks in advance.Best Regards,(お名前)