You originally wanted to send an email with an attached document to the person with your university email account, correct? But since it's not working, you are going to use your personal email account? I want to make sure I understand. If I have understood correctly, then I would say the following: I wanted to reach out to you because we want to accept our selected paper of seminar material. I have attached the document. My university email account is currently down, so I apologize for sending you the document from my personal account.

I wanted to reach out to you because we want to accept our selected paper of seminar material. I attached the paper. I wanted to reach out to you because we want you to accept our seminar material. The paper is attached. Sorry for not use university email because it does not work. Sorry I did not use the university email, it did not work.