On Dell Latitude I run Ubuntu 18.10. Originally the wifi symbol had a question mark which I got rid of by switching off connectivity check in privacy settings. This didn't fix the problem. Network adapter is Qualcomm Atheros QCA9565/AR9565. This didn't happen previously on other wifi connections.
The webpages report error ERR_CONNECTION_REFUSED, which I find quite weird. Restarting network connection doesn't fix it.