Intermittently, after entering user and password, the initial page from the router displays but is locked up. Closing Chrome and re-accessing the router works OK the second time. The PC is Windows 10 and up-to-date. The router Firmware is 380.68.
I should have been more explicit. I am using an insecure (http) access. I just enter router IP address into the browser URL line. Confirmed with Chrome info that it is not a secure site.
What happens if you use Firefox? You should always have a second browser available, anyway, in case the main one really breaks and loses all Internet access. (Not counting Edge or IE,)