Nest Cam (battery) will not stay connected to Wi-Fi

The checks in more detail

Put the node where it can see a window that faces the camera. The camera supports the 2.4 and 5 GHz bands, but its range is best on 2.4 GHz, so if the camera sits far from the router, make sure the router's 2.4 GHz band is on and joinable. A router that merges both bands under one name can steer the camera to the weaker 5 GHz, so a separate name for 2.4 GHz may help. Use WPA2 security, since older or unusual modes can stop a join. Reserve an address for the camera and avoid very wide channels. If the router has a feature that limits connections or a guest network without internet, the camera may be placed on it by mistake.

Check the battery as well: a low battery makes the camera sleep deeper and reconnect slowly, and it may show offline, so charge it. If the camera was working and stopped after a router or password change, join it to the new network through the app's settings, or remove and add it again. An outage in Google's service can show cameras offline, so check the Google Home status. Restart the router and the camera by removing it from the mount for a minute. Make sure the app is current. If it still fails to hold a connection near the router and fully charged, contact Google support with the camera's serial number from the base.

A battery camera has to balance its radio against its battery, so the quality of the link also decides how long a charge lasts: a camera that struggles to find the router keeps its radio on longer and drains faster. If the battery life is short as well as the Wi-Fi poor, the signal is probably the cause of both. Moving the router, or adding a node near the camera, often doubles the time between charges. Avoid placing the camera directly against a window with a metal blind or low-emissivity glass, which blocks signals as well as light. In winter, cold reduces battery capacity and cameras may go offline more often; bring the battery indoors to warm up before charging.