peculiar problem with my website, https://mickwebsite.com

I have a peculiar problem with my website, https://mickwebsite.com, which I host on my home desktop computer using IIS 10. The website is accessible over mobile data but not over WiFi.

• Specifically, I am not able to run the website from a browser [Chrome] on the host computer;
• While I can run it from another device [my phone] using mobile data, I am unable to run it over WiFi from that device.
• I have verified that my website is accessible by mobile data from anywhere in the world using Hostinger.com

I get this response: This site can’t be reached. mickwebsite.com took too long to respond.

I ran a Win 10 trouble shooter to access my website and received this feedback...

• resource (mickwebsite.com) is online but isn't responding to connection attempts.
  and this...
• The remote computer isn’t responding to connections on port 443, possibly due to firewall or security policy settings, or because it might be temporarily unavailable. Windows couldn’t find any problems with the firewall on your computer.

I have never had any "security policy" settings?

I have done and checked all of these...

• port forwarded 80 and 443
• redirected http to https
• allowed Chrome through the firewall
• removed all chrome add-ons
• tried with an alternate browser: MS Edge
• tried with firewall off as well as on
• ensured all proxy options set to off

I have also done these...

• power off-on computer
• power off-on modem
• ipconfig /flushdns
• netsh winsock reset

Suspecting the problem is a setting in the modem, I ran all of the tests in the modem Troubleshooting > Network Diagnostic Tools. All returned successful results

I ran the Wi-Fi Spectrum Analyzer Data in the modem. It returned a page of data with no obvious error indications.

I am at the end of anything I can think of to try. Any help appreciated
🙂
Mick