Agents not answering

Mattermost Server 11.9.0 (Cloudron),
Edition: Team (Upgrades/Trial optional)
Agents Plugin: agents‑v2.5.1 (GitHub)
Open WebUI as a middleware
LLM Backend: LM Studio via Tailscale, chat/completions requests are HTTP 200

Result in mattermost: no agent answer. „Sorry! The LLM did not return a result.“

serverllog: notification blocked: AI agent response to user-initiated action

Repro: in DM and channel constantly

Help appreciated. Thanks.