Cannot send mail from Outlook 2007 after upgrade

Yesterday I installed the win10 "November major upgrade" to my Win10 system. I upgraded to Win10 couple of months ago from Win7. There were some problems then but I managed to fix them. After yesterday's upgrade some of the problems reappeared. I had hard time to recall HOW I fixed it couple of months ago, but this one I just cannot get over:
When trying to send mail from Outlook 2007, this error appears: :Error 452.4.1.0 Policy violation . Your host xxx.xxx.xxx.xxx has no valid reverse DNS.: and mail resides in the "to be sent" folder. No need to say that before upgrade all worked OK and that this cannot be real error, because I can send mails from the same LAN via other devices. It seems that the upgrade changed something. The inability to send e-mail costs me lot of money and I need this to be solved asap.

Have you tried going to Programs and Features > right click at Microsoft Office 2007 > click CHANGE > click Repair ?
If that does not fix anything, consider Uninstall > Reinstall option.

davidhk said:

Have you tried going to Programs and Features > right click at Microsoft Office 2007 > click CHANGE > click Repair ?
If that does not fix anything, consider Uninstall > Reinstall option.

No such entries in my Programs and Features

Roman Krejci said:

No such entries in my Programs and Features

Did you install MS Outlook 2007 as a standalone ?
Your Program and Features has to have a listing of the program.

Are we talking about the same program ?
I am assuming you mean Microsoft Office Outlook 2007. Yes ?
Or, are you using Outlook.com which is a free web-based email program.

davidhk said:

Did you install MS Outlook 2007 as a standalone ?
Your Program and Features has to have a listing of the program.

Office 2007 was preinstalled on my comp when I bought it. I also have some legacy installations of programs that are parts of different versions of Office. Program and Features lists Office 2000 (I have only Access installed from 2000 ver) . It does not list Office 2007. Anyway - all worked OK until yesterday.

RE : Office 2007 was preinstalled on my comp when I bought it.

How long ago ?
I find it odd that Office 2007 was given away free, unless it was a "trial" version.
Even then, it should be listed in Programs and Features. It HAS to be.
Something does not add up.
Microsoft Office has never been free.

I paid for the Office 2007 and the manufacturer preinstalled it for me. In 2009 I think

Roman Krejci said:

I paid for the Office 2007 and the manufacturer preinstalled it for me. In 2009 I think

It makes even less sense. You bought a retail version, manufacturer installed it for you, and yet it does not show up in Programs and Features ?
That's impossible. All programs installed must be listed in Programs and Features.

Well, you do have the product key of Office 2007 do you ?

It's easily possible. And Programs and Features lists Office 2000 from which Installed only Access.
Anyway, the REAL problem is what caused Outlook 2007 to stop sending mails.