[Virus Error] in invoice email subject

I have all my automatic invoices set in Invoice Ninja to BCC them to my spare email so I can confirm that emails are sent okay. Everything has always worked fine, but today I noticed that one of the emails had the subject line:
‘[Virus Error] New invoice R-0722 from businessNameHere’

What would cause this to happen? I have never seen this reported before.

Cheers.

Hi,

I found this, maybe it will help.

https://discussions.apple.com/thread/251059672?sortBy=best

Thanks, that solved my issue. Must just be a glitch with my email host (iCloud)