How to solve this? Error #2: stream_socket_enable_crypto(): Peer certificate CN

We have the same problem as described in a thread by @naa986

https://www.ads-software.com/support/topic/connection-failed-error-2-office-365/

Connection failed. Error #2: stream_socket_enable_crypto(): Peer certificate CN=*.xxxxxx.de' did not match expected CN=smtp.office365.com' [/home/xxxxxxxx/public_html/wordpress/wp-includes/PHPMailer/SMTP.php line 468]

@mrwalt Did you contact your web host and find a solution? If so: What did tehy do?