hMailServer IP got blocked, what should I do?

I'm using hMailServer application in order to host my own mail server. I'm currently hosting three domains (I just buy the domain and host them in my machines)

Everything is doing well, all my accounts works properly when sending and receiving. The problem I have now is that if I send emails in large scale my IP gets blocked.

Two days ago, I've sent 2500 emails (75 emails 10 minutes in 10 minutes) and I did not get any trouble (for what I could see).

Yesterday, I've tried to send 10000 emails (again, 75 emails 10 in 10 minutes) and it stopped because my IP got blocked. I can't tell you guys why or how, but after a few hours it was unblocked, and it was certainly not me.

So, if I go to MX Lookup Tool and filter from Reverse DNS, I get warnings saying:

1) SMTP Reverse DNS Mismatch - Warning Reverse DNS does not match SMTP banner
2) SMTP Tls, - Warning does not support TLS

The problem "Reverse DNS Mismatch" should be solved with my ISP or with the company where I bought the domain?

The problem "Reverse DNS Mismatch" should be solved with my ISP or with the company where I bought the domain?

Your ISP.

The TLS warning is good information, but not a "problem", will not lead to spam flagging.

Make sure your forward and reverse DNS, and HELO match. Ie: the software is configured to use mail.example.com, the IP it uses reverses to that same hostname, and that hostname forward lookup returns the same IP address.

See also this question for some good information: Prevent mail being marked as spam