Connecting a static IP

I know that I can't use port 25!

I don't understand why my SMTP server is not sending mail on port 587 or 465?

I can't read anything on that page outside the numbers and the Latin letters (never been good at Cyrillic or languages that use it).  That doesn't look like any sample Synology Mailplus config page on their support site.  You could try unchecking the base SMTP option to see if that'll force it to the others, though I'm not sure if this is defining what it will accept or what it uses to transmit.

This is Synology Version 7.1.1

All instructions use screenshots of version 6.2.2

I tried unchecking the SMTP checkbox - in this case, sending mail to local users stops working.

In the window with port 25 it is indicated that these are local users.

But when sending a letter to an external box, the server still tries to send it on port 25

Business customers can request port 25 be unblocked.

In network practices page https://about.att.com/sites/broadband/network
Port 25/TCP may be blocked from customers with dynamically-assigned Internet Protocol (IP) addresses to protect systems from becoming a mail relay for SPAM.
 
But I have paid for static ip addresses, In addition, I received the correct PTR record.  so can this port be unblock ? 

I certainly cannot unblock it.