API call gives 404 Error after update to Mattermost 11

Troubleshooting
1

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Summary
A ansible playbook using the community.general.mattermost module throws a ‘404 Error’ Channel not found after update to Mattermost 11

Steps to reproduce
Update from 10.8.0 on DB MariaDB (migrated via MySQL → PostgreSQL)
to
Server Version: 11.1.0
Desktop Version: 6.0.1
Database Schema Version: 143
Build Number: 19159932738
Database: postgres

Expected behavior
No changes in urls, channels, ansible code or users. Only Update of Mattermost (and DB migration from mysql to postgres)

Incoming webhook can still be seen in mattermost config, same id as before.

Observed behavior
Mattermost logs are clear, 404 error resource “Channel” not found,

{“timestamp”:“2025-11-19 10:53:15.434 +01:00”,“level”:“debug”,“msg”:“Incoming webhook received”,“caller”:“web/webhook.go:61”,“webhook_id”:“XXXXX”,“request_id”:“9ffkdr9e93fb9qggo5scja6j4c”,“payload”:“{“text”:“redacted”,“username”:“semaphore_alarms”,“icon_url”:“https://docs.ansible.com/favicon.ico\“,\“channel\”:\“Semaphore_Provisioning\”,\“props\”:{\“webhook_display_name\”:\“Alarms\”},\“attachments\”:null,\“type\”:\”\“,\“icon_emoji\”:\”\“,\“priority\”:null}”}
{“timestamp”:“2025-11-19 10:53:15.434 +01:00”,“level”:“debug”,“msg”:“Failed to handle the payload of media type application/json for incoming webhook XXXXX.”,“caller”:“web/context.go:118”,“path”:”/hooks/XXXXX”,“request_id”:“9ffkdr9e93fb9qggo5scja6j4c”,“ip_addr”:“10.76.1.116”,“user_id”:“”,“method”:“POST”,“err_where”:“incomingWebhook”,“http_code”:404,“error”:“incomingWebhook: Failed to handle the payload of media type application/json for incoming webhook XXXXX., HandleIncomingWebhook: Couldn’t find the channel., resource “Channel” not found, id: TeamId=yf1b8u5ry783ipfmqi974e9rdr&Name=Semaphore_Provisioning”}
{“timestamp”:“2025-11-19 10:53:15.434 +01:00”,“level”:“debug”,“msg”:“Received HTTP request”,“caller”:“web/handlers.go:175”,“method”:“POST”,“url”:“/hooks/XXXXX”,“request_id”:“9ffkdr9e93fb9qggo5scja6j4c”,“status_code”:“404”}