I have similar thread on this titled scheduled reboot. I have same case as you, my other 960L was dead for 5 weeks (but router says connected) and only come back when there was a power outage.
Have you setup a daily scheduled reboot of 960L? it is on the Maintenance section.
I have not yet set up a scheduled reboot. As I had indicated in some of my 2330L postings that also had connectivity issues, I tried scheduled reboots as a remedy but I actually LOST some otherwise working 2330L cams on scheduled reboots and decided that was not a good solution for the 2330L. I was hesitant to try that on this camera but this cam, unlike the 2330L, seems to be "partly awake" since it shows itself online. Maybe it is still awake enough to successfully execute a scheduled reboot.
By the way, the solution that seems to be working so far for the 2330L is putting a remote power switch (DSP-W110) in front of it. The wifi switches have bailed out my wifi 2330L cams a few times already in the last month. They should bundle them.
Duh.....I thought I was going to setup the reboot option on the 960L right after I wrote this posting. Just checked........It has been online for the last 3-4 days (reset due to a power outage) and it was up earlier today. It is now offline again. Too late to try scheduled reboot. Will need to wait for another power outage.