Plantuml plugin not working on SB+ on my work laptop

SilverBullet+
1

My work laptop is running W11. I have the latest version of SB+. I started a new space and installed LogeshG5 plantuml plugin under Libraries via 'Install from URI'.
A plantuml block get rendered as Error: Offline.
When I run a local SB server on the same space, it gets rendered fine on Edge browser.

I thought this could be a firewall issue. The silverbullet-app.exe had no rules, so I added rules to allow traffic on domain, private and public networks. To no avail...

I figure it must be something limiting the SB+ executable, since it works on Edge. Also tried running SB+ as (local) admin, but that makes no difference.

Somebody here has more ideas towards a solution? Or propose some steps for troubleshooting?

2

I have a similar issue with the Excalidraw plugin made by the same dev. Works fine in browser/PWA but not in SB+, it errors with "widget not found" or something similar. Did raise an issue on their GH, but wondering if there is something in SB+ that causes a problem.