That could definitely be the issue. This is likely the Captive Portal Assistant. It attempts to access a certain Google page to verify that you have internet access. If you don't, it will pop up this window in an attempt to catch a redirect to a login form.
That could definitely be the issue. This is likely the Captive Portal Assistant. It attempts to access a certain Google page to verify that you have internet access. If you don't, it will pop up this window in an attempt to catch a redirect to a login form.