Windows Security Won't Let Me Connect to the Internet

I have a Windows 10 (somewhat recently updated) Lenovo laptop. Ever since about a week ago, every time I try to connect to the Internet, a box pops up. It says "Windows Security" and asks for my username and password, has "Domain:" written beneath where it asks for the password, then has the options "OK" or "Cancel". If I cancel, it does not allow me Internet access, and if I don't give the correct username and password, it does not allow me Internet access. I have tried to put everything I can in the fields. I tried just writing my username, (which is my microsoft account I use to sign into my computer and the password to it, right?) alone. I have also tried writing it like, //Servername/Username. Am I doing it wrong?
Is there another way to get passed this?
I went in the Advanced Sharing Settings and turned off Password Protected Sharing, and reset, which didn't work.
So I also tried going into the Advanced Sharing Settings and switching from the recommended "Allow windows to manage homegroup and user accounts." to, "Use User Accounts and passwords to connect to other computers" as well, and reset, which did not seem to work either.
My lap top also does not seem to have many Homegroup options. It just says that this device cannot use a Homegroup.
Is there any other setting changes I should try or ways that I can get passed this at all? My roommate who uses the same connection doesn't have this issue.