DMSS works on home Wi-Fi but not on mobile data: what to check
Start with a comparison, not a reset. On the same phone, test one camera at home on Wi-Fi and then with Wi-Fi switched off. Confirm the phone itself has internet access on mobile data. Write down the exact error and whether all channels fail.
Check how the recorder was added
An entry using a private LAN address is intended for a reachable local network; it is not automatically reachable over the public internet. Dahua documents IP and P2P as different ways to add a device. A private-address setup may require an authorised VPN or a different approved remote-access arrangement. Do not expose the recorder by opening router ports as a quick fix.
If you use P2P, read its status at the recorder
Record whether P2P is online or offline. Offline calls for checking the recorder's internet path. Online does not prove that the phone's account, permissions or connection are correct. Avoid deleting a working device entry until you know how to restore access.
Isolate the symptom
If every channel fails only on one phone, compare with another authorised user's device where available. If only one channel fails on both networks, record that separately. If a lower-quality stream works but a high-quality stream fails, include that observation in your support request; it is a clue, not proof of a particular bandwidth or codec fault.
Stop before risky changes
Do not factory-reset, guess firmware, disable the firewall or disclose credentials. If an installer or IT team manages the system, ask them before changing network settings. Keep any account-recovery issue with the authorised owner and the appropriate official support route.
Need help? Start with a free suitability check
Tell us the device model and a short description. We check whether your case fits our service before inviting you to pay. This suitability check is free, with no obligation or payment details required; it does not include troubleshooting. For a small, clearly defined question, €15 written help includes one targeted instruction and one follow-up, with up to 15 minutes of expert review. If a fault needs investigation, the €39 diagnosis covers likely causes and prioritised next steps. We confirm the appropriate scope before payment. Applicable taxes are shown at checkout. Live remote support and guaranteed repairs are not included.
Have ready: device model, phone OS, DMSS version, exact error, the Wi-Fi/mobile comparison, P2P status and the last change before the fault. Redact identifying details and never send passwords.
Technical reference: https://dahuawiki.com/DMSS/Add_Dahua_Device_via_IP
CCTV Rescue is independent of Dahua.