Collabora Online connection refused by 127.0.0.1

Hello,
After installing collabora online with Docker i can configure it successfully in the Collabora Online settings (setiting up 127.0.0.1 and disabling ssl) in Nextcloud, but when i try to open any supported richdocument file i get the error
Connection refused by 127.0.0.1

Nextcloud 21.0.4

How to debug this? how to check any log file to address me to the solution?
Please help thanks!