Receives, replies but does not send

[lottomano]

I have a strange problem, the emails arrive, I can reply but I cannot send an email.
Rdns and all okey,

Test: http://leafdns.com/index.cgi?testid=BEC32922
Mail test result: https://www.mail-tester.com/test-o02re7qca

All the ports seem to be open and working, I have tried everything but I understand why I cannot write an email, but I can receive and reply.

A help?

[Sandeep]

check maillog /var/log/maillog  and ask your server porvider/ISP if they allow emails via port 25

[lottomano]

My provider says they have no problem and port 25 is active.
However miscrosoft, it says my IP address is not mitigated.
I use 0.0.0.45. from 0.0.0.1 to 0.0.0.63 are not mitigated.
from 0.0.0.64 to 0.0.0.123 are mitigated.
What should I do?