Dahua camera can log in in speed mode, but not compatible mode.

The possible reason is that Dahua camera's speed mode and compatibility mode use different network protocols. The ultra-fast mode of Dahua camera may adopt more efficient network transmission protocol, and the compatible mode adopts traditional network protocol.

Login failed due to different network protocols. This may be because your monitoring equipment or network environment does not support the protocol used by the camera in extreme speed mode.

To solve this problem, you can try the following steps:

1. Make sure that the firmware of your monitoring equipment and camera has been updated to the latest version. Sometimes, device updates can fix compatibility problems.

2. Check whether your network environment supports the protocol used in camera extreme speed mode. You can contact the network administrator or equipment manufacturer for consultation.

3. If you can't solve the problem, I suggest you contact the technical support department of Dahua or camera manufacturer and ask them for advice. They may provide more specific solutions.

Please note that I am giving general suggestions, and the specific solutions may vary depending on the device model and network environment.