I see an exclamation point next to the WiFi icon
This means there is an issue with your cellular signal or you simply need to "use this network as is." Check your APN settings and confirm that Name is set to nextplus go and APN is set to wholesale. If you still see the exclamation point, tap the notification that says "Sign-in to network." The webpage will direct you to Nextplus GO My Account. Tap the menu button (three dots) on the top right and choose "Use this network as is." Check to see if you're properly set up by placing a call or sending a text using Nextplus.