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?

  • 1
    I hope you found a solution an can share, I'm facing the same problem. I think the problem is around TLS configuration on Windows 2019 server, I used iiscrypto /template best and also copied the setting from another server but still have the problem. guess some setting not under my control
    – Domex
    Jun 30, 2022 at 15:54

2 Answers 2


After much trial and error on a site we have, that used to work with Windows Server 2012 but stopped after an in-place update to Windows Server 2019, disabling TLS 1.3 Server registry resolved this.

Initially I thought it was fixed by unchecking the 2 Site Binding checkboxes for:

  • Disable HTTP/2
  • Disable OCSP Stapling

But I think that was possibly coincidental timing.


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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