Problem with collabora_online and nextcloud 20.0.1

Can’t connect to collabora server. By entering the server data, the connection is OK.

After refreshing the page, the server becomes unavailable again

apache+php-fpm7.4+mariaDB. Nextcloud 20.0.1
Collabora server on another server. Working 100% tested with next cloud 18.
Help me, please. At least which way to look.

same problem. does anyone have advice?