If you are using an old mail client or an old OS, it is possible the software does not support TLS 1.2 or 1.3 and therefore your emails are not working anymore on your computer.
If your emails don’t work it means your mail client (Mail, Thunderbird, Outlook) does not support TLS 1.2 or 1.3. It is therefore not up to date and is a major security risk for your data. Please update your mail client as soon as possible to fix the issue.
Why It’s Dangerous to Use Outdated TLS Security Protocols
https://www.venafi.com/blog/why-its-dangerous-use-outdated-tls-security-protocols
First, please update your OS and Email client software!
How to view and change the Windows Registry Settings for the SSL/TLS Protocols on a Windows Host
https://community.tenable.com/s/article/How-to-view-and-change-the-Windows-Registry-Settings-for-the-SSL-TLS-Protocols-on-a-Windows-Host