Help Internet connection troubles

[Nomad of Norad]

I have a really frustrating problem. One place I am at once a week for several hours has an open Wifi connection that 90% of the time doesn't give me an Internet connection, and instead of falling back on the clearly-available cellphone-tower connection for my Internet, it simply declares No Internet Connection and goes into Offline Mode. This is a gigantic hassle.

The particular Wifi is some thing where you aren't being asked to enter a password to access the wifi, instead you are shunted to some nonstandard interface that asks you to link this up with your Facebook account, apparently this is also so that they can monitor your activities and make sure you're not going to anything improper. This is at a church, with a large congregation, and the problem seems to be that, since smartphones these days seem to all be configured to automatically go through a wifi first, you wind up probably with at least a 1000 cellphones all trying to connect automatically to the Net via the open wifi... and I'm guessing this massively, MASSIVELY overwhelms their system every Sunday morning... so after a moment or two of Internet working, the Wifi suddenly lists itself as No Internet, and stays that way indefinitely.

My issue is, 1> I'd like to BLACKLIST that wifi connection altogether if necessary, and 2> I WANT my Internet to stay on 100% of the time thru the cellphone tower when I'm at that location. There doesn't seem to be any way whatsoever to tell my Samsung S7 phone to blacklist that wifi, and as far as I can tell I've got things configured such that if no wifi is available it SHOULD fall back on the cellphone-tower-based Internet service. But instead it just instantly goes to Offline Mode.

How do I fix this? This is driving me round the bend.

 

[Nomad of Norad]

Okay, I swung by my local T-Mobile store a couple weeks ago and mentioned the issue I was having. One of the guys there went though my settings and tweeked something, but said he couldn't really see why it would be doing something like that.

Well, I haven't really been able to test if I'm still having the trouble at that same location, but I now have use-wifi turned off. On the other hand, I am still seeing "No Internet, Going into Offline Mode" pop up sometimes here and there... but if I then immediately go open the web browser, pages load without obvious trouble. What is causing that message? oO

 

[Nomad of Norad]

Well, I'm now reasonably sure that "No Internet" message is something the Facebook app is saying. but which pops up independently of actually having the app open on screen... such that it looks to the uninitiated as if the Android OS itself is saying that. It gripes the heck out of me that it gives such a general-sounding message like that, rather than instead saying something like "Facebook App cannot reach home. Going into offline mode." Instead it's "No Internet, Going into Offline Mode." Even tho Internet still works for everything else on the device at that moment. Seriously, whoever programmed that needs to get a Gibbs slap from everyone on the entire Internet. Oo

As for the other problem.... I simply turn WiFi OFF when I'm at church, so it doesn't even try to use that useless connection.