Yahoo not accepting Gmail - Authentication error

[Ham_and_Jam]

Anyone help with this please.

I am sending emails to various recipients, but one Yahoo account is rejecting .It has been fine for years for this week its no longer accepting them.

A blocked email message from Yahoo suggests its a DKIM error.

I thought that Gmail automatically set up DKIM on their accounts, as I can't find anywhere in the Gmail app that allows me to do anything with DKIM. Am I missing it somewhere?

This is a basic Gmail account, not workspace, business or paid for,

[skyebear]

Have you checked your emails meet Yahoo's most recent requirements?

https://senders.yahooinc.com/best-practices/

Are other Yahoo recipients ok?

Have you emailed the problem address from another Gmail or non-gmail account to see if delivered ok?

[eeLee]

are you sending from Gmail web client or something else?

[Ham_and_Jam]

eeLee said:

are you sending from Gmail web client or something else?

Sent from Outlook desktop on windows PC and from iPhone iOS email app.

[Ham_and_Jam]

skyebear said:

Have you checked your emails meet Yahoo's most recent requirements?

https://senders.yahooinc.com/best-practices/

Are other Yahoo recipients ok?

Have you emailed the problem address from another Gmail or non-gmail account to see if delivered ok?

That kind of goes back to my original post, how do I authenticate emails from Gmail? I’ve looked everywhere in the Gmail app and there isn’t an option to do this.

[eeLee]

Ham_and_Jam said:

Sent from Outlook desktop on windows PC and from iPhone iOS email app.

From Outlook, are you set up with an app-specific password or did you add a Gmail account?
On the phone, is it the Gmail App? Or Mail.App? Did you also add the Gmail account to the phone?

In short, I would expect a Gmail-authed account on both to pass DKIM, SPF and DMARC when routing out via Gmail services, going another route (another SMTP server) will cause borkages like you're seeing.