Based on your description, it seems like your iPhone is not connected to the network. To understand the root cause of the issue please share the screenshot of the error showing in your iPhone while you are trying to connect to the network
If you have unleashed app in your iPhone please share the error showing in the app.
Here is where you can upload the image/photo :
you can also drag it to the chat
Please let us know if you have any queries in this regard.