Cognito verification code emails no longer being sent

Has anybody had an issue with forgotten passwords and Conito not sending the verification code via email to users?

As far as I am aware there has been no code changes or AWS service changes in this area for quite some time but emails are no longer sent.

We are using amplify in the client front end to trigger this and I can see it hitting the AWS services and returning a 200.

Code being called:

await Auth.forgotPassword(
        email,
      );

Usually this would send an email with a code in there which the user could then use to change their password.

Account recovery it set to email only, so it isn't going anywhere else. SMS is also disabled.

General emails from AWS are being sent from our account with no problems. Also, cognito is sending other emails out correctly, such as temporary passwords.