I have the same problem: Today my camera suddenly wasn’t accessible via WLAN anymore. Several reboots didn’t help – I could only access the camera if I plugged in a LAN cable. Finally I found this thread, removed the SD card – and eventually WLAN was working again.
To make sure, I then unplugged the LAN cable and started pinging the camera’s IP: As soon as I inserted the SD card, the camera stopped responding. Removing the SD card again made no difference, I had to reboot the camera to make it work again (reproduced several times).
I tried to reformat the SD card in my iMac – still didn’t work. Finally I once again connected to the camera using a LAN cable and reformatted the SD card via the „SD management“ section of the camera’s admin interface, but to no avail: As soon as I unplugged the LAN cable, with the SD card still inserted, the camera stopped responding. I also tried disabling “SD recording” completely, but this didn’t help either.
Some more notes:
* During my experiments today I upgraded the firmware from 1.12 to 1.23 – made no difference.
* The SD card originally was quite full (200MB of 16GB remaining), but this was expected as I had SD recording configured to “Keep Free Space: 200 MB”
So for now I just use the camera without SD card. But I would be REALLY interested in the cause of this bug. And a fix, of course.