Fortigate SSLWeb: accessing subfolders fail thru nextcloud web

we are accessing nextcloud web interface thru fortigate ssl web vpn page, everything works well except cannot access subfolders,
when i check subfolder url is duplicate like below;

any ideas?

We have exactly the same Problem: FortiGate 200E v6.2.3, NextCloud 18.0.3

Any Ideas?

We also have the same problem. Has anyone found a solution?

Nextcloud is generating WebDAV links (/remote.php/dav/…) in the webclient links (/files.php/…/files?dir=…) when accessing Nextcloud through the Fortigate SSL Webproxy (as per the example url posted by OP) instead of normal webclient links directly to the file or folder.

Additionnal information: we have added the Fortigate SSLWeb url ( as per OP example url) in trusted_domains and its IP to trusted_proxies.