|A couple of things to check. |
Check your internet proxy through
connections[tab at top]
lan settings[radio button at bottom]
if there is a proxy server selected, and you were unaware that you were supposed to have one. click the button that says use a proxy server. and if you like send me the address of the proxy server.(this may help us get to the bottom of the issue)
second suggestion is to download and run malwarebytes, and see if anything pops up.