unrecoverable error after <> attempts: unexpected status code 400

Hi,
I have seen few posts related to this error, but none seem to work for me, hence reaching out. We are trying to integrate pagerduty with Alertmanager. Prometheus was installed using operator in our environment and I have followed the pagerduty documentation to integrate the alertmanager. But whenever I do the curl command to simulate the alert, I see above errors in the alertmanager pod.

Given below is my alertmanager config. I tried with both prometheus and events v2 , but both gave the same error. Integration key was provided as k8s secret (pager-int). Any clues as to what could be wrong is much appreciated.

Thanks,
Raghu

Name: pgduty
Namespace: prometheus
Labels: alertmanagerConfig=Example
Annotations:
API Version: monitoring.coreos.com/v1alpha1
Kind: AlertmanagerConfig
Metadata:


Spec:
Receivers:
Name: pagerduty-example
Pagerduty Configs:
Routing Key:
Key: int-key
Name: pager-int
Route:
Group By:
cluster
Group Interval: 5m
Group Wait: 30s
Receiver: pagerduty-example
Repeat Interval: 12h
Events:

Hi Raghu,

Thanks for reaching out to PagerDuty.

Could you please reach out to our PagerDuty Support team at support@pagerduty.com so we can investigate further.

If you could please add as much detail to your ticket as possible that will most helpful.

Best regards,

Rebekah Dawkins
Technical Support Specialist I
PagerDuty.com