The short answer
Check the batteries first, because a lock reports plenty of charge long after it lacks the current to hold a radio connection. Then check whether the lock uses Bluetooth to your phone or Wi-Fi through a bridge, since the fixes are entirely different. A bridge needs to be within range of both the lock and the router, which usually means the hallway rather than beside the router.
A smart lock is a battery-powered radio device mounted on a metal door in the draughtiest part of the house. Nothing about that is friendly to wireless connectivity, which is why connection problems dominate the complaints about them.
Step 1: batteries
Locks prioritise the motor over the radio. When batteries weaken, the connection degrades long before the lock stops turning, and the battery indicator is usually optimistic. If the lock has been in service for months and has become unreliable, fit fresh batteries before troubleshooting anything else.
Use good quality alkaline or lithium cells, not rechargeables, unless the manufacturer specifies otherwise. Rechargeable cells have a lower voltage, which some locks interpret as nearly flat from the start. Lithium cells perform substantially better in cold weather, which matters for an external door in winter.
Change all the batteries at once, not just the ones that seem weak. Mixed cells cause the pack to behave like the weakest one, and it is a false economy on a device you do not want failing unexpectedly.
Step 2: know which radio you are troubleshooting
Smart locks use one or more of:
- Bluetooth to your phone when you are close. Works with no network at all, and only when you are nearby.
- Wi-Fi, either built in or through a plug-in bridge, for remote access.
- Zigbee, Z-Wave or Thread to a hub, which is the most reliable option because it is designed for low-power devices.
If remote access fails but the lock works when you stand next to it, Bluetooth is fine and the Wi-Fi or hub path is the problem. If it fails at the door too, it is Bluetooth or the lock.
Step 3: the bridge position
This is the most common configuration error. A Wi-Fi bridge must be close enough to the lock to hold a solid Bluetooth connection and close enough to the router for good Wi-Fi. People plug it in next to the router, where the Wi-Fi is perfect and the lock is out of range.
Position the bridge within about 5 metres of the lock
Closer is better, and with as few walls as possible. The hallway near the door is usually correct.
Check the Wi-Fi signal at that position
Use a phone. If it is marginal there, add a mesh node rather than moving the bridge further from the lock.
Keep it off the floor and out of sockets behind furniture
Same rules as any wireless device.
Avoid sockets shared with a large metal appliance
A radiator, a mirror or a metal console table between the bridge and the lock costs more signal than the distance does.
Check the bridge's own status light
Most indicate lock connection and network connection separately, which tells you which half is failing.
Step 4: network settings
- 2.4GHz only. Virtually all smart locks and bridges are. If your router uses one name for both bands, setup often fails because the phone is on 5GHz. Split the bands temporarily.
- Reserve a fixed IP address for the bridge in the router, which prevents disconnections when the lease expires.
- WPA2 or mixed mode, since WPA3-only networks break many of these devices.
- Do not use a guest network with client isolation, which prevents local communication.
- Check the DHCP pool is not full, which silently prevents new connections.
Step 5: the phone side
For Bluetooth locks, the phone is half the system:
- Grant the app location permission, which Android requires for Bluetooth scanning.
- Set the app to unrestricted battery use, or it will be suspended and fail to connect when you arrive.
- Allow background activity, since auto-unlock depends on it.
- Check that the phone is not connected to too many Bluetooth devices at once.
- Reinstall the app if it has stopped working after an update, which re-establishes permissions cleanly.
Always keep a physical key and know where it is. Smart locks fail: batteries die, firmware updates go wrong, and bridges lose connection. Any lock that cannot be opened with a key, or has no mechanical override, deserves careful thought before installation on the only door you use.
Step 6: mechanical causes
A lock that struggles to turn draws more current, drains batteries quickly and behaves erratically. Before blaming the electronics:
- Check the door aligns properly with the frame, since a door that has dropped makes the bolt bind.
- Lubricate the cylinder with a graphite or PTFE lubricant, not oil, which attracts dirt.
- Check the thumb turn or adaptor is seated correctly and the mounting is tight.
- Recalibrate the lock in the app after any mechanical adjustment, since it learns the travel of the bolt.
A lock that has become noisy or slow is telling you about the door, not the software.
Why does my smart lock work at the door but not remotely?
Because remote access goes through a bridge or hub, and that path has failed. The Bluetooth connection you use at the door is separate and clearly working.
How long should smart lock batteries last?
Typically six to twelve months, less in cold weather and less if the door binds. A dramatic drop in battery life usually means the mechanism is stiff rather than the battery being faulty.
Where should I put the Wi-Fi bridge?
Within a few metres of the lock, with good Wi-Fi at that position. If the Wi-Fi there is poor, improve the coverage rather than moving the bridge closer to the router.
Can I put a smart lock on a guest network?
Only if client isolation is off, since isolation blocks the local communication the app and bridge need. A separate network for smart devices without isolation is the better arrangement.
What happens if the batteries die completely?
Most locks have a mechanical key override or external contacts to apply emergency power from a battery. Know which yours has before you need it, and keep a physical key accessible.
The order
Fresh batteries, all at once. Work out whether the failure is Bluetooth at the door or the remote path through a bridge. Move the bridge to within a few metres of the lock and confirm Wi-Fi is good there. Reserve a fixed address, use WPA2 and avoid isolated networks. Check the app’s battery and location permissions on your phone. And if the lock is noisy or slow, fix the door before anything else.
