Migration fails: Failed to connect to target Plesk server by Plesk API: urlopen error Errno 10061

Symptoms

Migration fails with the following error after clicking Prepare migration :

Error: Failed to connect to target Plesk server by Plesk API: <urlopen error [Errno 10061] No connection could be made because the target machine actively refused it>

The following error could be found in "%plesk_dir%"\\var\\modules\\panel-migrator\\sessions\\<timestamp>\\debug.log :

+|D|MT|core.utils.common.http_xml_client|||API request to https://203.0.113.2:8443/enterprise/control/agent.php:
=|D|MT|core.utils.common.http_xml_client|||<?xml version="1.0" encoding="utf-8"?>
=|D|MT|core.utils.common.http_xml_client|||<packet version="1.5.2.1">
=|D|MT|core.utils.common.http_xml_client|||  <server>
=|D|MT|core.utils.common.http_xml_client|||    <get>
=|D|MT|core.utils.common.http_xml_client|||      <stat/>
=|D|MT|core.utils.common.http_xml_client|||    </get>
=|D|MT|core.utils.common.http_xml_client|||  </server>
=|D|MT|core.utils.common.http_xml_client|||</packet>
=|D|MT|core.utils.common.http_xml_client|||
+|D|MT|core.connections.checker|||Exception:
=|D|MT|core.connections.checker|||Traceback (most recent call last):
..........
=|D|MT|core.connections.checker|||URLError: <urlopen error [Errno 10061] No connection could be made because the target machine actively refused it>

Plesk on a target server is accessible on custom ports (e.g. 8444 instead of 8443 for HTTPS, and 8881 instead of 8880 for HTTP).

Cause

Migrator tries to connect to a target server via API on port 8443, but Plesk site in IIS works on a different port.

Resolution

Add binding for port 8443 for HTTPS in IIS Manager on a target server:

1. Go to Server Manager > Tools > IIS Manager > SERVER > Sites > pleskcontrolpanel > Bindings > Add...

2. Specify the following parameters:

   Type: https
   IP address: All Unassigned
   Port: 8443
   SSL certificate: Default Certificate
   

   and click OK.

3. Restart the pleskcontrolpanel site with Restart button on the right.