Emails from Outlook bounce back from all yahoo and sky emails with error message

error message "Your message wasn't delivered. Despite repeated attempts to deliver your message, a connection to the remote server was closed abruptly.

Contact the recipient by some other means (by phone, for example) and ask them to tell their email admin that it appears that your email system is unable to connecto their email system. Give them the error details shown below. It's likely that the recipient's email admin is the only one who can fix this problem.

For Email Admins
This often indicates the recipient's firewall SMTP fixup setting or other firewall settings are preventing the SMTP protocol negotiation from succeeding.

For more information and tips to fix this issue see this article: https://go.microsoft.com/fwlink/?LinkId=389361.

For Yahoo: returned '550 5.4.318 Message expired, connection reset (SuspiciousRemoteServerError)(450 4.4.318 Connection was closed abruptly (SuspiciousRemoteServerError))'
3/8/2024 8:44:42 PM - Server at mx-eu.mail.am0.yahoodns.net (188.125.72.73) returned '450 4.4.318 Connection was closed abruptly (SuspiciousRemoteServerError)'

For sky: returned '550 5.4.300 Message expired -> 421 4.4.2 Connection dropped due to SocketError'
3/8/2024 8:39:33 PM - Server at 188.125.72.73 (188.125.72.73) returned '421 4.4.2 Connection dropped due to SocketError'

I cannot ask all my contacts that have yahoo or sky accounts to change their firewall settings. There seems to be a problem with Microsoft!