[Samsung Galaxy J5 (2016) ROMs, Kernels, Recoveries] RootedLee:
Thank you @xXPR0T0TYPEXx for your ROM (and @Freak3672 for the "marketing" .. ;)), I finally applied it yesterday with stock settings, no custom check-marks during install.

Today I was trying 1st time with this ROM to connect to a public WiFi I had successfully connected to before with this J5 running an older 6.0.1 ROM. Right after tapping onto the "Open Wi-Fi Networks Available" Notification, I get an error pop-up "CaptivePortalLogin has stopped". I found that app in Apps Manager as a System app, force-stopped, cleared Cache, tried to log in again, same thing. Force-stopped again, cleared Data, tried to log in one more time, same thing.

As a work-around, accessing the portal login via a browser works after a bit of fiddling.

Airplane mode with WiFi activated.

I verified via file manager that there is a System/app/CaptivePortalLogin/CaptivePortalLogin.apk. It is v.7.0.5/ 104kb, and from buildinfo.xml/ AndroidManifest.xml inside:

BUILD="257.1.1"

CREATE date="2018-08-08"

VERSION value="19271750"

With my 6.0.1 ROM before any public WiFi had always been fine.

Yes, I cleared System, Data, Cache, Dalvik Cache via TWRP prior to install.

When googling CaptivePortalLogin has stopped, I learned that this was an issue of the 7.1.1 beta/ public preview experienced by everybody who tried the 7.1.1 beta. While the final 7.1.1 was not out yet, someone with a Pixel 2 XL solved this error back in Oct. 2016 in his 7.1.1 preview install by applying an updated Google Connectivity Services APK from APKMirror (but did not state which version).

"Google Connectivity Services includes Wi-Fi Assistant, which automatically connects you to high-quality public Wi-Fi, and secures those connections by transmitting your data through a secure Virtual Private Network (VPN) managed by Google."

[EDIT, see Update 4 below]Obviously the Connectivity Services apk either updated or replaced the CaptivePortalLogin module.

Before installing the latest GCS update from just a few days ago, I thought I'd hear what you folks can say about this. Anybody else who connects to public WiFi with this v.4.0 ROM?

What makes me wonder is: did a pre-7.1.1 module make it into this ROM? Or is this ROM (partially) based on the 7.1.1 preview?

[UPDATE 1]: APK mirror even offers many different flavors of CaptivePortalLogin. Maybe simply re-install their Samsung 7.0.5, reboot, and if that does not work, try the Google 7.1.2?

[UPDATE 2]: accdg. to APK Mirror, CaptivePortalLogin.apk v.7.0.5 (this ROM's) was targeted for Android Nougat 7.0, API 24! Google's v.7.1.2 apk, however, was targeted for Nougat 7.1.1!! So it seems somehow the CaptivePortalLogin.apk from 7.0 and/or 7.1.1 Preview made it into this ROM?

[UPDATE 3]: since this is a system app, regular install fails -> an installer zip for TWRP would need to be made. I've run out of time for now, though.

[UPDATE 4]: at least the latest Google Connectivity Services apk does NOT contain ANY apk inside, so it cannot replace the CaptivePortalLogin.apk..

[UPDATE 5]: the APK Mirror CaptivePortalLogin.apk 7.0.5 is not just smaller (51 kb) but also almost a year older than the SEP 8.5 one. From buildinfo.xml/ AndroidManifest.xml:

BUILD="247"

CREATE date="2017-09-18"

VERSION value="15024893"

[UPDATE 6]: I just successfully flashed Google's 7.1.2 (build 25 accdg. to AndroidManifest.xml inside) which was actually created for 7.1.1 and is the most recent for Nougat from APK Mirror. It correctly displays as 7.1.2 in Settings/ Apps/Sys apps.

It'll take me most likely until Monday before I can test-login into a public WiFi again.

In case you can reproduce this error and want to help debug, you find two zips for install in TWRP attached, one to flash Google's 7.1.2 build 25, and another one to restore back to SEP 8.5 7.0.5 build 257.1.1 (I test-flashed and verified that one, too, before attaching here).

[UPDATE 7]: A brief interim update: S U C C E S S via work-around: CaptivePortalLogin_7.1.2.zip flashed via TWRP + regular install of Google Connectivity Services (I used the latest v.3.4 prod (3326)).

Exclusive installs of either GCS v.3.4 or CPL 7.1.2 were not enough, not even after restart, clear both apps cache, data bla bla

Actually I prefer public wifi via VPN, anyway... I'd prefer it not be from Google, but still better than no VPN, I dare say..

[UPDATE 7]: S O L V E D, see my posting here.