IIS 10 – Fix ERR_CONNECTION_RESET When Using HTTPS on Windows Server 2019

httpsiisiis-10ssltcp

I have a site hosted in IIS 10 on a server running Windows Server 2019. I've set up an HTTPS certificate with Let's Encrypt. Attempts to view the site with http:// work normally, but when I enter https://, I get an ERR_CONNECTION_RESET error in Brave (which is based on Chromium). The problem is the same from any client computer I've tried.

On the server, Wireshark shows the request being received, but after four packets, the process concludes with my computer sending an "RST, ACK" to the server. Then it seems to repeat again with four more packets. I don't think the requests are even reaching IIS because they aren't being logged by IIS.

Wireshark List

Here is a Wireshark file with the packet information:
https://1drv.ms/u/s!AvTC3qfYkjI9oeAytsS_3PrgrA7FXQ?e=XCdtJR

Can someone please suggest a way forward?

Best Answer

I discovered my Web host was not allowing TLS communication over port 443. My host said, "We had an application group called web browsing set in the rule that apparently did not have every TLS protocol in the group that your website was set to support." Windows Firewall is disabled in favor of some separate firewall that is outside my control, and the firewall was not set correctly for port 443.

So if you're having a problem like mine, ensure that TLS is being allowed on port 443.

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