ninkasi

You can always use no-ip. It's free with the catch that you have to renew/verify your ddns every 30 days. They will send you an email to remind you when it is about to expire.

Are you using an iPhone by chance? sounds like it might be an issue with IPV6. the iPhone will only use IPV6 addresses if they are available from your service provider. Most of dahua's stuff uses ipv4. ipv4 and ipv6 won't communicate to each other.

This is happening because you have multiple channels set to record in the event settings under record on both of these cameras. In the event motion detect settings there is a setting that says record channel. You probably have all the channels highlighted. This will allow you to record video on other channels when the channel you are on detects motion. Here is a great video that covers how to properly set up motion detection in smart PSS. This software is actually MontavueGO but its identical to smart PSS