Heyy. For my DHI-NVR408-8P-4KS2 firmware, I'm currently using firmware V4.000.0000001.3What NVR do you have and which firmware version are you using on your NVR?
There was a firmware update to get SMTP working.
Hope this helps
P.S. Just to clarify. SMTP email has been configured in the NVR and got a pass in the test. However, IVS/Motion detection does not send emails of image/video recordings...