sounds weird~ how about clear cache of Firefox? If the issue still exists, it's recommended to send email to tplink support with exact hardware and firmware version of your C7.

Do you mean after the FW of NC220 updated? What's the OS version of your smart phone? It's better to reset the camera and unbind the current account.

ngerencn wrote It has been recovered, thank you very much :-) Great :)

which smart product do you have? Have you registered an cloud account? Certainly, you need to download the related APP on your Android.

How about restart your computer? And you do make sure the LAN ip address of D7 is 0.X? This is a little weird.

Do you mean wired or wireless connection? It's already the latest firmware. If it's wireless connection, try to set a fixed wireless channel. If it's both wired and wireless connection, it's...