The problem started about 10 days ago (10/01/2019) after some changes were made to the Walmart in-store WiFi configuration. Since then I can't connect to the in-store WiFi from my LTE ZTE Maven Z812 smartphone.
The phone seems fine, connects to all other networks. Other phones also connect just fine to the Walmart in-store WiFi network. But when I try to connect to Walmart WiFi with Z812 I get an error WiFi connection failed and no IP address.
Resetting the adapter, forgetting the network, and rebooting the phone did not help.
I noticed that the store recently split 2.4 GHz and 5 GHz access points, there are different ESSIDs for them ("Walmartwifi 2.4" and "Walmartwifi"). The Z812 does not see the 5 GHz AP but sees 2.4 GHz just fine. I tried connecting to 2.4 GHz AP from another smartphone and it works just fine.
Any ideas what might be wrong? Is Walmart blocking certain models/manufacturers from using in-store WiFi?
Additional info: I don't think it is MAC filtering. It feels like something is broken in the IP negotiation process, but I don't understand why this specific phone and this specific network.