What is the problem?
Cannot connect to the PI using the web interface. Was running old version of Octoprint on Pi 3 b+ without problems. Popup appeared stating that I am running an old Python and must upgrade. Did a backup and downloaded Pi imager. Followed the instructions for imager and rebooted the Octopi with new image. Now the message "Unable to connect" appears in firefox when trying to connect. The error in Microsoft edge is: ERR_CONNECTION_REFUSED. For a split second prior to showing the "Unable to connect" message, there appears a screen that typically appears when you visit an unsafe website and your options are to proceed (unsafe) or go back. But that screen instantly disappears and the "unable to connect" screen stays in its place.
What did you already try to solve it?
I tried the image process again. I tried to turn off my firewall. I tried to connect using the local hostname and the ip address. I looked at my router settings to determine the PI's IP address. I pinged the PI and connected to the PI using putty. I changed PIs IP address to a static IP. I tried everything in the FAQ although most/all of it was not applicable because the PI is connected to the network just fine. I looked at a lot of other posts here. I think based on everything I've done, the problem lies in the invalid self-signed security certificate the author warns about. But the problem might also lie in the fact netstat reports nothing listening on port 80. One post I read mentioned a proxy program was not running and causing the problem.
Logs (syslog, dmesg, ... no logs, no support)
I cannot connect so that limits my logs. I will supply any logs requested. Here is netstat showing nothing is listening on port 80.
pi@raspberrypi:~ netstat -tulpen (Not all processes could be identified, non-owned process info will not be shown, you would have to be root to see it all.) Active Internet connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State User Inode PID/Program name tcp 0 0 127.0.0.1:631 0.0.0.0:* LISTEN 0 8979 - tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 0 13758 - tcp6 0 0 ::1:631 :::* LISTEN 0 8978 - tcp6 0 0 :::22 :::* LISTEN 0 13760 - udp 0 0 0.0.0.0:5353 0.0.0.0:* 108 10096 - udp 0 0 0.0.0.0:68 0.0.0.0:* 0 15529 - udp 0 0 0.0.0.0:631 0.0.0.0:* 0 14488 - udp 0 0 0.0.0.0:56959 0.0.0.0:* 108 10098 - udp6 0 0 :::5353 :::* 108 10097 - udp6 0 0 :::44294 :::* 108 10099 - pi@raspberrypi:~
Additional information about your network (Hardware you are trying to connect to, hardware you are trying to connect from, router, access point, used operating systems, ...)
I am using a Windows 10 vmware virtual machine connected to an RT-AC68R wirelessly that the Octopi is also connected to wirelessly.