I’ve faced the same issue for a short time.
I have no clue what was the trigger. But during I was facing the issue, I found that the cause of this issue. And it might be “Automatically Detect Settings” in Internet Option.
(type “Internet option” on you windows, select “Connections” tab, and click “LAN settings”)
As the expected behavior, if you use TWLP mode, this item must not be checked.
But when i got this issue, this item was automatically checked for some reason.
I also could check and un-check this even though Z-App is ON.
In addition to this, if I use TWLP mode, “Use automatic configuration script” should be filled with loopback PAC file, which looks like http://127.0.0.1:xxxx/localproxy-xxxxxxxx.pac, AUTOMATICALLY, and this must not be editable when Z-App is ON.
But it was not filled even after I turned on Z-App, and I could edit it.
Anyway, when I uncheck the item, the issue was solved.
I do not know why this item was checked by itself. Maybe there should be another fact for that.
But if you are still facing the issue, could you just try to uncheck “Automatically detect settings”? and check if the issue was solved?
This is most likely workaround. I mean, we need to find out if there is another cause of issue.