Sorry for the delay in responding.
Yes I use XAMPP. I checked file httpd.conf, it has “Listen 81” and “Server Name localhost:81.” File httpd-ssl.conf has “Listen 443.” So this is all as it should be.
Checked phpMyAdmin > Databases > Structure > wp_options – this has “https://localhost:81/pcpopbytes.” So again all apparently correct.
To check what other applications might be using this port, I ran command “netstat -a -n -o | find “81””. Applications using this port apart from XAMPP are Chrome browser and Team Viewer, the latter installed a few months ago. So Team Viewer seems to be the problem.