Hi @<1750327622178443264:profile|CleanOwl48> , it's not a cookie domain issue, when a P{lotly background image is set, Plotly used JS to fetch it, but it omits the cookie when the image and webapp are not on the same site.

we have a workaround, if you properly set the fileserver URL for webserver nginx it will redirect calls from /files to fileserver, and if the UI has WEBSERVER__fileBaseUrl set it will allow the UI to rewrite the call for the image through nginx reverse proxy.
this way the request to fetch Plotly background image stays on the same site and auth cookie get sent.