@wurtel_385647887286479
Can you try to disable the SSL/TLS when configuring? If it can't work, please provide the packet capture to our support team for further check. Submit a request – Reolink Support

Yes, SSL/TLS was off when I tried. I'll send a packet capture.

Please add an option to configure SMTP server without authentication. I have a local SMTP server that accepts email on port 25 from the local network. However I get an error:

480: Incorrect SMTP server info or port. Please correct it and try again

I see it connects, but when the EHLO response doesn't show any AUTH capabilities it disconnects.