Nextcloud can't connect to OnlyOffice but elinks can

Nextcloud version: 15.0.4
Operating system and version: Ubuntu 18.04.2 LTS
Apache or nginx version: Apache/2.4.29 (Ubuntu)
PHP version: PHP 7.2.15-0ubuntu0.18.04.1

When setting up OnlyOffice with the address of the server (127.0.0.1:4430 in my case) I get a “Erreur durant la tentative de connexion (Demande incorrecte ou délai d’attente dépassé)” message (maybe translated in “Error while trying to connect (Wrong demand or delay timed out)”. When I try to use port 8000 (the http port of OnlyOffice) I get an error about mixed content.
The weird thing about this is that elinks (a command line web browser) can access http://127.0.0.1:8000 and https://127.0.0.1:4430 without any problem so I’m guessing it’s not a problem in my OnlyOffice config.

Is this the first time you’ve seen this error? (Y/N): Y

The output of your Nextcloud log in Admin > Logging:
Logs

The output of your config.php file in /path/to/nextcloud (make sure you remove any identifiable information!):
config.php

The output of your Apache/nginx/system log in /var/log/____:
Apache logs of the day

Hi @Tzigamm

You should never post passwort salt and secret from your config anywhere. Please remove the values asap.

Thanks for letting me know ! It’s fixed

Has anyone else encountered this problem/has an idea on how to fix it ?