Q: TC no longer a part of my network but my wifi network is still working, mostly. What has happened?

What color is the light on the Time Capsule?

I would try unplugging it, waiting 20 seconds or so, and plugging it back in. Note that, if there are other devices that are still successfully connected to the Time Capsule, you should disconnect them first.

Just to be clear, can you still see the TC in AirPort Utility, even though it says it's not part of the network? If so, what do you see when you click/tap on its icon?

When you go to File > Configure Other and enter the details, try going to the "Internet" tab and press the Renew DHCP Lease button. Then try connecting again.

There are others who are more seasoned Time Capsule users than I am who may drop in here, but my only other suggestion would be to reset the Time Capsule. If you don't want to wait for other suggestions, see Resetting an AirPort base station FAQ - Apple Support. If you end up having to do a factory reset (the last step), note that it says:

Important: Factory Default reset doesn't erase the contents of any hard drives associated with the base station.

So your data is safe.

A lot of people today are having the same issue.. something is happening but I am not sure of any update that has gone through in the last few days that could have messed things up.

Do you happen to have your iCloud ID setup in the TC?

Sometimes just press the reset for 1-2sec.. this is the soft reset will actually get it working again. When you do that all the passwords return to default.. ie no wireless password and main TC password will be public.. It will only last 5min but might help you locate the TC.. otherwise as per stevejobfan0123 .. do a factory reset and start over.

People are saying this also has not helped but I am sure if the setup can be configured with static IP it should work. We will need your full network layout if you continue to have issues.. ie what is your main modem.. make and model.. is it a pure modem or modem router.

Is the TC plugged directly to the modem via the WAN port using ethernet and setup in bridge or router mode??

As much info as possible can help.

Unfortunately I am not sure on that. However, a hard reset, as opposed to a factory default reset, retains the configuration. Have you tried that?

Ah, I was not aware that this was a more widespread issue. FWIW this does not occur for me in iOS 9.3.4 or OS X El Capitan.

capricorn54, you are in better hands now so I will sign off, but I'll still check on this thread later. Best of luck!

capricorn54 wrote:

 

The TC is set up as a router. My Apple ID is logged in the TC.

Thanks for those details.

Some people are suggesting the Apple ID is the issue.. I am very unconvinced but it could be worthwhile testing it.

Motorola Surfboard SB6141

That just happens to be our least favourite modem. There is some funny business that happens between the SB series modems and the Apple AC model routers. Neither are faulty but they just don't play well together.

Your setup is great.. UPS for your network gear is exactly my method to keep networks stable.

But in your case something needs to go. The fault is weird in that many people experience no issues for first year if they get through the first install, but it can start into the second or third year.

I am guessing your TC is the AC model??

Who is your ISP? And are you on IPv6 yet??