Why does it say CAUTION - EXTERNAL E-MAIL at the top of incoming emails?

To help highlight potentially spoofed/spam/phishing emails, from 01 September 2020, any email not originating from an @aber.ac.uk address will have a warning inserted at the top as follows:

[RHYBUDD! E-BOST ALLANOL / CAUTION! EXTERNAL E-MAIL]

This does not mean that the email is spam, just that it has not come from @aber.ac.uk so extra care should be taken when using any links included or replying.

This will not affect emails sent from AU email accounts from home or mobile devices