Running OnlyOffice with Docker-Compose - WOPI - Connection refused while connecting to upstream

Docs API
10

Hi @Alexandre

I added a javascript to post the message:

function setOnlyOfficeForcesave() {
	
	console.log('setOnlyOfficeForcesave.....');
	var iframe = document.getElementById('wopi-iframe');
	iframe = iframe.contentWindow || (iframe.contentDocument.document || iframe.contentDocument);
	if (iframe) {
		console.log('post message...');
		iframe.postMessage(JSON.stringify({"c": "forcesave","key": "Khirz6zTPdfd7","userdata": "sample userdata"}), "*");
		console.log('post message completed!');
	} else {
		console.log('iframe not found!');
	}
}

The postMessage is executed without errors but I did not see any changes in behaviour.
I created a tar file from my documentserver logs. How can I provide you this file? I can not upload the file into this forum (?).

===
Ralph