[Message: Not Found] using uir static or dynamic. No Alerts are send to Teams channel

[jadatoin]

Describe the bug
Hi, sorry for bother but I will need some help.
Our prometheus-msteams configuration was deployed and the tests are working, but using static/dynamic uri I got message: "Not Found" on each.
Version
OS: Ubuntu 22.04.03
Binary Prometheus-MSTeams v1.5.2
Binary Alertmanager v0.25.0

Test
curl -X POST -d @prom-alert.json http://myfqdn.dom:2000/_dynamicwebhook/ (Works)
curl -X POST -d @prom-alert.json http://myfqdn.dom:2000/alertmanager/ (Works)

Config Parts
Service Daemon:

[Unit]
Description=Prometheus-msteams
Wants=network-online.target
After=network-online.target

[Service]
User=root
Group=
Type=simple
ExecStart=/opt/prometheus-msteams/prometheus-msteams -teams-request-uri alertmanager \
          -http-addr myfqdn.dom:2000 -config-file /opt/prometheus-msteams/config.yml \
          -template-file /opt/prometheus-msteams/card.tmpl

prometheus-msteams config (config.yml):

connectors:
  - alertmanager: "https://myO365.webhook.link/aaa/bbb/vvv/xxx"

Alertmanager config (alertmanager.yml)

receivers:
  - name: alert_channel
    webhook_configs:
      - send_resolved: true
        url: 'http://myfdn.dom:2000/alertmanager'
route:
  group_by: ['alertname','severity']
  group_wait: 1m
  group_interval: 15m
  repeat_interval: 1h
  routes:
   - match:
      severity: warning
     receiver: alert_channel

   - match:
      severity: critical
     receiver: alert_channel

templates:
- '/etc/prometheus/alertmanager_templates/*_alert.tmpl'

Prometheus config:

global:
  scrape_interval: 15s 
  evaluation_interval: 15s 

# Alertmanager configuration
alerting:
  alertmanagers:
  - static_configs:
    - targets:
      - 'myfqdn.dom:9093'

rule_files:
   - '/etc/prometheus/alert.rules.yml'

Expected behavior
I expected having the alerts incoming into MSTeams and emails. But only receiving alert mails, prometheus-msteams is not sending msgs to Teams Channel. How I can check logs? and any idea if something is wrong with my config.

Thanks for any help.