Help Wifi connects then immediately disconnects after odd popup

[makaiguy]

Samsung Galaxy S7 on Verizon, Android 7.0

Western Digital N750 Dual band router, with 4 networks set up (regular and guest nets on both 2.4 and 5.6). My normal wifi connection is to the regular 2.4 net.

A week or so ago I was connected to my normal home 2.4 net when I had a popup saying something about some abnormal wifi activity being detected and asked if I wanted to block this, or words to that effect (wish I had kept notes on exactly what it said). I clicked the button to block it.

Since then I have not been able to connect to that same home net. It goes through the motions, says I'm connected then immediately disconnects and reconnects to one of the other 3 home nets. None of my other devices have any trouble connecting to this net, so it seems to be a problem with the phone only. I cannot find anything about how to remove this block that I apparently added.

I have told it to "forget" the problem net, but it still cannot hold the connection after I reconnect and add in the password.

Elsewhere I've seen recommendations to turn off Smart Switch, but that hasn't helped.

And of course, I've rebooted the phone a number of times.

Any suggestions?

 

[svim]

If you installed any kind of anti-virus/anti-malware app on your S7, try disabling all its features, reboot your phone, and see if that makes any difference in re-connecting to your home WiFi network. Those AV utilities often create just as many network connectivity issues as what they allegedly claim to solve.
Following the similar topic, you could try to boot your phone up into its Safe Mode and see if you can reconnect to your WiFi while in Safe Mode. When in Safe Mode, your phone is running a 'clean' Android without any third-party apps auto-launching in the background. If you can connect while in Safe Mode, at least you know there's just some app you've previously installed that's the cause, the problem then being determining just which one. Could be one you installed just around the time the problem started, or a previously installed one that just got updated and then started to create a problem.
http://www.hardreset.info/devices/samsung/samsung-g930f-galaxy-s7/faq/safe-mode/

Another thing to try is disable IPv6 in your router. Even though IPv6 has become quite prevalent there are still some (very) sporadic, odd connectivity issues with Android. Looking at the online manual for your router it appears to have a pretty extensive feature set, take a look at pgs. 31-35:
http://products.wdc.com/library/UM/ENG/4779-705072.pdf

You mentioned already trying to delete/re-add your home WiFi network in your phone's Settings
but have you already tried just creating a completely new SSID and seeing if that works out better? There could just be an issue where the old configuration info stored internally in your S7 is simply corrupted or otherwise preventing that particular WiFi network to connect. You also mentioned your phone will just switch itself to one of those other three networks so if that primary SSID is the problem with your S7 that might be something to try.

 

[psionandy]

I'm also assuming that you have rebooted the router?

 

[makaiguy]

Thanks, guys. Yeah, forgot to mention rebooting the router, which was one of the first things I did.

Shortly after posting that query I thought of just changing the SSID and gave that a try. Kinda hesitated because that meant having to reconfigure the wifi on all my devices connecting to that net and was a bit concerned with messing up my DirecTV, which would incur great social problems on the home front. But I'm basically more familiar with configuring wifi than messing with the inner workings of cell phones, so I went ahead and now all is well again.

If that popup ever crops up again I'll pay a lot more attention and try to see where it came from. And I'll keep this thread bookmarked to have some things to investigate if needed.

Thanks again.

 

[svim]

Yeah, I was assuming it would be a hassle to reconfigure a new primary WiFi network when there were a lot of other devices involved but in the long run it's more or less necessary if your S7 is also your primary phone.
Anyway, be sure to check if your router has any firmware updates (if they don't automatically notify you) and it wouldn't hurt to go through your current router configuration settings to make sure things are locked down properly.
This 'RouterCheck' does a scan and checks your router settings for basic security issues. The interface could use a little polishing but I think its superior feature is the excellent documentation it provides for the items it checks:
https://play.google.com/store/apps/details?id=com.Sericon.RouterCheck.client.android&hl=en
That initial popup message you encountered does sound odd. Hopefully it was a one-off thing.

 

[makaiguy]

WD got out of the router business several years ago -- which is why I got such a good deal on this router, I think. Latest firmware (installed) is from 2012, and I doubt there will be any future updates.

Thanks for that RouterCheck app. Very useful and gave me a couple of things to lock down, hopefully to prevent EVER seeing that popup again.

 

[makaiguy]

I think I've found the culprit in a Verizon installed app "Security & Privacy". Under "Wi-Fi security" it listed 2 blocked networks, one of which was the home net in question's original SSID. I removed that entry, but now that I've changed the SSID, I can't easily go back and try connecting to the original SSID to see if that would have fixed it.

[Edired to add:] The description in the app for blocked networks is "Networks you always disconnect from", which sounds exactly like what I was seeing.

 

[svim]

 

[NikiD]

I think I've found the culprit in a Verizon installed app "Security & Privacy". Under "Wi-Fi security" it listed 2 blocked networks, one of which was the home net in question's original SSID. I removed that entry, but now that I've changed the SSID, I can't easily go back and try connecting to the original SSID to see if that would have fixed it.

[Edired to add:] The description in the app for blocked networks is "Networks you always disconnect from", which sounds exactly like what I was seeing.

Thank you so much for your advice! Suddenly today my phone and home WiFi were not playing well together! It's taken just about the entire afternoon & evening, along with many different options to try. Finally, your suggestion solved my problem and I am once again able to connect to my home WiFi! I was totally surprised to see my home network blocked and out of the blue.
Thanks, again!

I think I've found the culprit in a Verizon installed app "Security & Privacy". Under "Wi-Fi security" it listed 2 blocked networks, one of which was the home net in question's original SSID. I removed that entry, but now that I've changed the SSID, I can't easily go back and try connecting to the original SSID to see if that would have fixed it.

[Edired to add:] The description in the app for blocked networks is "Networks you always disconnect from", which sounds exactly like what I was seeing.

 

[makaiguy]

Glad I could help. Congratulations to you on taking the initiative to find existing solutions!