How to enable TLS 1.2 on Mail 16.0 (Monterey OS)

Apple Mail v16.0 on Monterey is automatically attempting TLS 1.2 handshakes with IMAP4 servers where it then authenticates against that Mail servers certificate. If that certificate is wrong or out of date, the TLS 1.2 handshake does not occur.

In Apple Mail, the Window > Connection Doctor lists the Mail servers that you are connected,. Select the Mail server entry with the green connection dot, and IMAP, then click the button named Show Detail and then click Check Again. A flurry of content will scroll in that detail window and you are looking for the string: [kCFStreamSocketSecurityLevelTLSv1_2 ].

There are no steps to enable it. It is already enabled.

you can try working with your email providers tech-support along with the connection doctor in Mail to determine why the handshake is failing

Hey IgorfromTokyo,

Welcome to Apple Support Communities. We understand that you're having an issue sending mail from your Mac after a change in the security type. We'd like to help.

It will first be helpful to see if the Mail Settings you see are correct. Start by looking at this resource to see if Apple has the Mail settings saved for your account under Mail Settings Lookup: Mail - Official Apple Support

If you don't you may need to reach out to IONOS to get those exact details. This resource on their website can be useful in this situation: https://www.ionos.com/help/email/other-email-programs/setting-up-an-ionos-email-account-in-apple-mail/

If you need to manually add those details, this can help: Add an email account to your iPhone, iPad, or iPod touch - Apple Support

Enter account settings manually 

If Mail can't find your email settings, then you need to enter them manually. Tap Next, then follow these steps:

1. Choose IMAP or POP for your new account. If you aren’t sure which one to choose, contact your email provider.

2. Enter the information for Incoming Mail Server and Outgoing Mail Server. Then tap Next. If you don't have this information, try to look it up.

3. If your email settings are correct, tap Save to finish. If the email settings are incorrect, you'll be asked to edit them. 

If you still can't set up your email account or save your email settings, contact your email provider

Also, we did locate that the TLS 1.2 security protocol is one that Apple Supports - TLS security - Apple Support

Hope that helps.

Take care!

The Mail settings appear to be the same for all my email addresses. So what next?

I have the same question and problem as IgorfromTokyo, but with my Hotmail.

Can you advise a step by step process to enable Mac Mail to work with TLS 1.2 please?

Thank you for the reply.

I saw the Connection Doctor. It shows the same positive results for all my emails, iCloud, Yahoo, and two Hotmail accounts.

No idea if the handshake is failing or not, frankly. I just suddenly had an email from MS to say that one of my accounts was not set to TLS 1.2. Worse still, they don't really say how to correct this, except upgrade. Too vague.

In speaking to a "techy" friend, he said that maybe a reset might be productive anyway, by deleting the hotmail accounts from Mail and then re-adding them fresh. If I suddenly have that problem in a couple of weeks, I'll try doing that. :-)