As a newb here, and no experience with the Lifu cams, I can only suggest that the likely issue is with your setup of the
DDNS server, and/or those server settings on the cameras...but.. you mentioned you are trying to connect "on the phone, at the office". So, if you CAN connect via phone elsewhere (your home's wifi doesnt count), then it is likely that you are trying to connect via the company wifi (vs the phones 4G), The company Wifi is likely blocking your attempt to connect, due to router security settings. If you CAN connect with your phone elsewhere, then disable the Wifi for data when at work and try it via 4G. If you CAN NOT connect from anywhere, then check and re-check the DDNS account you setup, and then confirm those settings are correct on the cameras. Also, make sure your home router allows for outside access for the camera port (80?) and related protocols (mentioned in the camera manual) which need to pass though the router's firewall.
Everyone want to do this themselves to save money on a pro, but when it comes to IP camera configurations, behind routers, accessed via mobile phones, the networking setup is commonly a bit too complex for those not experienced with network devices and related IP routing.
Good luck!
