Hikvision DS-2CD2346G1-I emails with no content

I have one of the above cameras which generally works very well. However, most days I get one or more emails generated by the camera with no attached files and the message:

"This message cannot be displayed because of the way it is formatted. Ask the sender to send it again using a different format or email program.

multipart/mixed"

There is no video recorded at the time the message is sent.

Has anyone else experienced this and is there a fix/ setting I'm missing. This new camera...

Hikvision DS-2CD2346G1-I emails with no content