Hi Community, 

how are you?

I own a QNAP TS-251D with 16GB of RAM.

Today I downloaded the Xeams_8.4.qpkg application package for the QNAP.

I did the initial configuration on the Xeams for QNAP, opened up my routers ports 25, 80, 443, 110, 143 to go to my Qnap local IP address.

Then I tested my open ports by using this website called portchecktool

This confirmed that the ports are open and that there are running services behind it.

I then created an A record on godaddy and called it mail.domain.com and pointed it to the public WAN IP address of my internet router.

The pop, imap, smtp services are operational status of RUNNING.

When I went to create the Let's Encrypt SSL certificate using:

hostname = mail.domain.com

Test certificate = ON

Challenge type = HTTP using XEAMS

I received the following error:

Although Xeams is configured to listen on port 80, the server is not listening. Make sure to restart Xeams after changing to port. Additionally, ensure no other process is listening on this port.

Come back this page once Xeams is successfully listening on port 80.

Xeams was restarted but still the same error and no other process is listening on port 80

I also received this other error:

Integrating Xeams with Let's Encrypt
Error
Although a web server is listening, it returns a 404 when trying to fetch a test file. This happens when the request from the Internet on port 80 goes to a different web server inside your network.

The only port 80 that is open is the one the QNAP web server, therefore I turned off the Qnap webserver, but the problem remains.

I spent 12 hours on this searching everywhere online, but I can't work this out.

I would appreciate if someone could help me. 

Thank you.

Best regards

ab6540183