Cannot Connect Cura to OctoPrint

[Nealtron]

I got a new PC and need to install Cura.

• Installed Cura 5.6
• Added my Ender-3 Pro printer profile
• Added Cura-OctoPrintPlugin
• Restarted Cura
• Opened the "Connect to OctoPrint" window
• Added my OctoPrint instance
• Set the API key
• Hit the request button
• The new window opens and I click "Allow" and closed the window.

No matter what, I've tried, it always shows "OctoPrint is not available", and the "Connect" button is always greyed out.

Troubleshooting I've tried:

• Windows firewall is disabled.
• Octoprint is on the same subnet as the PC, no routing or firewall in-between.
• If I click on "Open in browser...", it successfully loads the web interface for my OctoPrint instance.
• If I navigate to "<octoprint-url/api/settings?apikey=", the data loads in successfully in less than 10 seconds.
• I've attempted to setup the connection with HTTP and HTTPS.
• I've attempted to use FQDN and IP for the Address.
• I've attempted to use "Application Keys" as well as the "Global API" key.
• The plugin successfully discovers my octoprint server, and even shows the OctoPrint version, but it still displays "OctoPrint is not available" when configured.
• Added the instance with and without my HTTP username and password.
• Restarting Cura several times.

Any help would be appreciated.

[Nealtron]

I was able to establish a connection by restarting OctoPrint in Safe Mode.