OK... I have a similar problem on my mMS L650, too. Only my phone NEVER did connect to any public WIFI Service. As offered by my city downtown which is an asset. And tho this is only one issue, my service recently dropped ALL Windows Phones and products.
They were unable to offer me any help, tho before W10, the W8.1 responded to the help they could offer. I cannot find password Assistance for open public sites. But thought I did not need a password for public wifi. This is a smartphone, not a PC. Virtual Assistant can never make this distinction. Please help.