Cannot edit files

Hello everyone,
I’ve started a nextcloud+collabora online setup via docker compose, but when I try to edit a file the collabora online logs displays these errors which I can’t really understand:

frk-00040-00040 2021-02-22 18:08:00.768760 [ forkit ] ERR Failed to get the realpath of [/etc/timezone] (ENOENT: No such file or directory)| common/FileUtil.cpp:256
frk-00040-00040 2021-02-22 18:08:00.768842 [ forkit ] ERR Failed to get the realpath of [/etc/localtime] (ENOENT: No such file or directory)| common/FileUtil.cpp:256
wsd-00008-00446 2021-02-22 18:08:00.832224 [ docbroker_017 ] ERR WOPI::CheckFileInfo failed with 403 Forbidden| wsd/Storage.cpp:625
wsd-00008-00446 2021-02-22 18:08:00.832716 [ docbroker_017 ] ERR loading document exception: WOPI::CheckFileInfo failed| wsd/DocumentBroker.cpp:1429
wsd-00008-00446 2021-02-22 18:08:00.832779 [ docbroker_017 ] ERR Failed to add session to [/index.php/apps/richdocuments/wopi/files/3369_ocqs1a8dextc] with URI [https://cloudsrr.reply.it/index.php/apps/richdocuments/wopi/files/3369_ocqs1a8dextc?access_token=Vm8hIOCMz6ISDh0IHzGVUtQdIJ55Itgs&access_token_ttl=0&reuse_cookies=__Host-nc_sameSiteCookielax%3Dtrue%3A__Host-nc_sameSiteCookiestrict%3Dtrue%3Aoc_sessionPassphrase%3DKM2LmCmlhjF1PYSBncfpW%2BZry1XkajSIajL68dCcUyOWL0PSsUd9hdXLXRN0AEHMGyu8aqaWGxnJGvQ14sGlfw2ul64uLYPVp4d205wLJmywAX9X4z8WCGa8S2Slck3T%3Aocqs1a8dextc%3D3824f1c532f694b7aea1cb89b506b908%3Anc_username%3D815674C2-530D-4487-8749-3BFFC789EF01%3Anc_token%3DmpcvpDJJb1fuTGW7yIh8PKaCUS3Zicmg%3Anc_session_id%3D3824f1c532f694b7aea1cb89b506b908]: WOPI::CheckFileInfo failed| wsd/DocumentBroker.cpp:1391
wsd-00008-00446 2021-02-22 18:08:00.914027 [ docbroker_017 ] ERR No DocBroker found, or DocBroker marked to be destroyed. Terminating session ToClient-024| wsd/ClientSession.cpp:331
wsd-00008-00446 2021-02-22 18:08:00.914100 [ docbroker_017 ] ERR No DocBroker found, or DocBroker marked to be destroyed. Terminating session ToClient-024| wsd/ClientSession.cpp:331
wsd-00008-00446 2021-02-22 18:08:00.926428 [ docbroker_017 ] ERR Invalid or unknown session [024] to remove.| wsd/DocumentBroker.cpp:1468
kit-00447-00040 2021-02-22 18:08:01.320639 [ kit_spare_018 ] ERR Failed to get the realpath of [/etc/timezone] (ENOENT: No such file or directory)| common/FileUtil.cpp:256
kit-00447-00040 2021-02-22 18:08:01.320775 [ kit_spare_018 ] ERR Failed to get the realpath of [/etc/localtime] (ENOENT: No such file or directory)| common/FileUtil.cpp:256
wsd-00008-00039 2021-02-22 18:08:02.833416 [ prisoner_poll ] WRN Prisoner connection disconnected but without valid socket.| wsd/LOOLWSD.cpp:2087
sh: 1: /usr/bin/loolmount: Operation not permitted
frk-00040-00040 2021-02-22 18:08:03.848092 [ forkit ] ERR Failed to unmount [/opt/lool/child-roots/OON32l0ZSHvVfFG6/tmp].| common/JailUtil.cpp:68
sh: 1: /usr/bin/loolmount: Operation not permitted
frk-00040-00040 2021-02-22 18:08:03.889038 [ forkit ] ERR Failed to unmount [/opt/lool/child-roots/OON32l0ZSHvVfFG6/lo].| common/JailUtil.cpp:68
sh: 1: /usr/bin/loolmount: Operation not permitted
frk-00040-00040 2021-02-22 18:08:03.930011 [ forkit ] ERR Failed to unmount [/opt/lool/child-roots/OON32l0ZSHvVfFG6].| common/JailUtil.cpp:68
^C

What do you think could be the cause? Let me know what other info could be useful and I’ll post it!
Thank you,
Roberto