Undeliverable emails to my @hotmail.com account

My hotmail inbox isn't receiving any new emails.

Below is the error message. My hotmail email was auto forwarding to the google email listed below but other than that, no other connection.

The google email account works totally fine. The only thing that has changed in the last 24hrs is that I signed into my web Outlook account for the first time in ages and unticked the auto forwarding.

When I noticed an issue with my emails on Mac Mail (Outlook account connected to this), I signed back into the web Outlook and same problem - no new emails - and the auto forwarding was still ticked. Maybe I didn't save changes?

Weirdly, some - but not all - new hotmail emails auto forwarded through to the gmail account today. None of these hotmail emails appeared in my hotmail inbox.

I have sent test emails from various other accounts but nothing is getting through to the hotmail inbox. But I did receive something from ******@accountprotection.microsoft.com when updating my security settings.

I have sent test emails from the hotmail account and they have sent.

I have reset my password.

Any help on how to unblock whatever is going on here would be much appreciated.

[mx.google.com] rejected your message to the following email addresses: [(mod: PII redacted]@googlemail.com] Your message wasn't delivered because the recipient's email provider rejected it. [mx.google.com] gave this error: Your email has been blocked because the sender is unauthenticated. Gmail requires all senders to authenticate with either SPF or DKIM. Authentication results: DKIM = did not pass SPF [[hotmail.com]] with ip: [2a01:111:f403:c207::3] = did not pass For instructions on setting up authentication, go to https://support.google.com/mail/answer/81126#authentication d2e1a72fcca58-7a274ba58e0si2777686b3a.490 - gsmtp