Cannot get Nextcloud to open file in collabora server

My collabora CODE docker on unraid seems to be working fine in terms of it loading and no error occurs on startup.
It is active and showing green in my nextcloud admin panel.
when I try to open a file it loads and gives a cannot open file and the log from collabora docker reads the following error message:

wsd-00001-00035 2022-12-09 13:25:49.643996 +0100 [ websrv_poll ] ERR #30: Error while handling poll at 0 in websrv_poll: #30 (handshake): unknown. BIO error: 336151574, rc: -1: error:14094416:SSL routines:ssl3_read_bytes:sslv3 alert certificate unknown:
23433983284992:error:14094416:SSL routines:ssl3_read_bytes:sslv3 alert certificate unknown:…/ssl/record/rec_layer_s3.c:1528:SSL alert number 46
| net/Socket.cpp:448

Can anyone help me understand what it says and what I can do to fix it.

I am running nginx docker for reverse proxy.

cheers
Måns

it sounds like your COOL server doesn’t trust certificate presented by Nextcloud server.