When we send e-mails from AX 2012R2 sometimes the error "Failure sending mail. Unable to read data from the transport connection: net_io_connection closed" appears.
I have narrowed it down, the reason it sometimes appears is because of the SMTP server from Office 365 that did not accept TLS1.0 messages. 
Only problem is that we have used registry changes so AX should use TLS1.2.
What is the best solution to let AX 2012R2 only use TLS1.2?

I have searched for it online, but did not find a good anwser.

Does anyone have had this problem and know how to solve it?
You also can send the registry changes, so i could verify them with the ones we used.

Thanks in advance,

Paul